diff --git a/hub/filelib-web/src/lib/GrantsPanel.svelte b/hub/filelib-web/src/lib/GrantsPanel.svelte
index 3199707..f2e6301 100644
--- a/hub/filelib-web/src/lib/GrantsPanel.svelte
+++ b/hub/filelib-web/src/lib/GrantsPanel.svelte
@@ -84,7 +84,7 @@
   }
 
   async function revoke(g: Grant): Promise<void> {
-    if (!confirm(`收回「${g.principalId}」的 ${g.role} 授权?`)) return;
+    if (!confirm(`收回「${g.principalName}」的 ${g.role} 授权?`)) return;
     try {
       await api(`/database/api/nodes/${node.id}/grants/${encodeURIComponent(g.id)}`, {
         method: "DELETE",
@@ -133,7 +133,8 @@
               <td>
                 <span class="inline-flex items-center gap-2">
                   <span class="flex text-ink-3"><Icon name={g.principalType === "USER" ? "user" : "group"} size={14} /></span>
-                  <span class="font-mono text-[12px]">{g.principalId}</span>
+                  <!-- 展示名优先(后端已解析);id 作为 title 供排查。 -->
+                  <span class="font-medium" title={g.principalId}>{g.principalName}</span>
                   {#if g.isCreatorGrant}<span class="quiet">(创建者)</span>{/if}
                 </span>
               </td>
diff --git a/hub/filelib-web/src/lib/LibraryView.svelte b/hub/filelib-web/src/lib/LibraryView.svelte
index 5a65257..8babc96 100644
--- a/hub/filelib-web/src/lib/LibraryView.svelte
+++ b/hub/filelib-web/src/lib/LibraryView.svelte
@@ -63,7 +63,7 @@
     }
   }
 
-  const initial = $derived(($me?.userId ?? "U").slice(0, 1).toUpperCase());
+  const initial = $derived((($me?.displayName ?? $me?.userId) ?? "U").slice(0, 1).toUpperCase());
 </script>
 
 <div class="flex min-h-0 flex-1">
@@ -97,7 +97,8 @@
     {#if showUserFooter}
       <div class="flex items-center gap-2 border-t border-line-soft px-4 py-3 text-[12.5px]">
         <div class="flex h-6 w-6 shrink-0 items-center justify-center rounded-full bg-accent text-[11px] font-semibold text-white">{initial}</div>
-        <span class="flex-1 truncate text-ink">{$me?.userId ?? ""}</span>
+        <!-- 展示名优先;/me 取不到 User 行时后端已回落为 userId。 -->
+        <span class="flex-1 truncate text-ink" title={$me?.userId ?? ""}>{$me?.displayName ?? ""}</span>
         <button class="rounded-lg border border-line-soft px-2.5 py-1 text-[11.5px] text-ink-3 transition hover:bg-hover hover:text-ink" onclick={logout} title="退出登录">退出</button>
       </div>
     {/if}
diff --git a/hub/filelib-web/src/lib/types.ts b/hub/filelib-web/src/lib/types.ts
index f0bffd6..d39b00b 100644
--- a/hub/filelib-web/src/lib/types.ts
+++ b/hub/filelib-web/src/lib/types.ts
@@ -72,21 +72,6 @@ export interface ExportJob {
   readonly createdAt: string;
 }
 
-export interface Grant {
-  readonly id: string;
-  readonly principalType: "USER" | "GROUP";
-  readonly principalId: string;
-  readonly role: Role;
-  readonly isCreatorGrant: boolean;
-  readonly createdAt: string;
-}
-
-export interface GroupSearchResult {
-  readonly id: string;
-  readonly name: string;
-  readonly breadcrumb: string;
-}
-
 /** 成员组(ADR-0028);后端返回扁平列表,前端按 parentId/depth 拼树。 */
 export interface MemberGroupNode {
   readonly id: string;
@@ -114,6 +99,8 @@ export interface Grant {
   readonly id: string;
   readonly principalType: "USER" | "GROUP";
   readonly principalId: string;
+  /** 后端解析好的展示名(USER→displayName / GROUP→组名);取不到行时回落为 principalId。 */
+  readonly principalName: string;
   readonly role: Role;
   /** 创建者授权不可收回、不可改(契约 8.1)。 */
   readonly isCreatorGrant: boolean;
diff --git a/hub/src/database/filelib/grantService.ts b/hub/src/database/filelib/grantService.ts
index cbb9f05..e443004 100644
--- a/hub/src/database/filelib/grantService.ts
+++ b/hub/src/database/filelib/grantService.ts
@@ -25,16 +25,24 @@ export interface GrantDto {
   readonly id: string;
   readonly principalType: "USER" | "GROUP";
   readonly principalId: string;
+  /**
+   * 展示名(ADR-0029:后端负责把 id 解析成人看的名字,前端不二次查询)。
+   * USER → `User.displayName`;GROUP → `MemberGroup.name`;
+   * 取不到行(用户/组已删)时回落为 principalId,与 `/database/api/me` 同一回落语义。
+   * 纯展示字段:写路径仍只认 principalId,不得用它做任何授权判断。
+   */
+  readonly principalName: string;
   readonly role: FileLibRole;
   readonly isCreatorGrant: boolean;
   readonly createdAt: Date;
 }
 
-function toDto(grant: FileLibGrant): GrantDto {
+function toDto(grant: FileLibGrant, principalName?: string): GrantDto {
   return {
     id: grant.id,
     principalType: grant.principalType,
     principalId: grant.principalId,
+    principalName: principalName ?? grant.principalId,
     role: grant.role,
     isCreatorGrant: grant.isCreatorGrant,
     createdAt: grant.createdAt,
@@ -44,6 +52,35 @@ function toDto(grant: FileLibGrant): GrantDto {
 type Tx = Prisma.TransactionClient;
 type Deps = AccessDeps & { readonly prisma: PrismaClient };
 
+/**
+ * 批量解析 principal 展示名(两条 IN 查询,不做 N+1)。
+ * 组不按 archivedAt 过滤:已归档组的历史授权仍要能显示出名字来给管理员收回。
+ */
+async function resolvePrincipalNames(
+  tx: Tx | PrismaClient,
+  grants: readonly FileLibGrant[],
+): Promise<ReadonlyMap<string, string>> {
+  const userIds = [...new Set(grants.filter((g) => g.principalType === "USER").map((g) => g.principalId))];
+  const groupIds = [...new Set(grants.filter((g) => g.principalType === "GROUP").map((g) => g.principalId))];
+  const [users, groups] = await Promise.all([
+    userIds.length === 0
+      ? Promise.resolve([])
+      : tx.user.findMany({ where: { id: { in: userIds } }, select: { id: true, displayName: true } }),
+    groupIds.length === 0
+      ? Promise.resolve([])
+      : tx.memberGroup.findMany({ where: { id: { in: groupIds } }, select: { id: true, name: true } }),
+  ]);
+  const names = new Map<string, string>();
+  for (const u of users) names.set(`USER:${u.id}`, u.displayName);
+  for (const g of groups) names.set(`GROUP:${g.id}`, g.name);
+  return names;
+}
+
+async function toDtosWithNames(tx: Tx | PrismaClient, grants: readonly FileLibGrant[]): Promise<readonly GrantDto[]> {
+  const names = await resolvePrincipalNames(tx, grants);
+  return grants.map((g) => toDto(g, names.get(`${g.principalType}:${g.principalId}`)));
+}
+
 /** MANAGE 门禁:带 tx 时用调用方事务(与后续写同绳),不带时自开一个。 */
 async function requireManage(
   deps: Deps,
@@ -66,7 +103,7 @@ export async function listGrants(
     where: { organizationId: deps.organizationId, nodeId, revokedAt: null },
     orderBy: [{ isCreatorGrant: "desc" }, { createdAt: "asc" }],
   });
-  return grants.map(toDto);
+  return toDtosWithNames(deps.prisma, grants);
 }
 
 export interface PutGrantsResult {
@@ -137,7 +174,7 @@ export async function putGrants(
       where: { organizationId: deps.organizationId, nodeId: node.id, revokedAt: null },
       orderBy: [{ isCreatorGrant: "desc" }, { createdAt: "asc" }],
     });
-    return { granted, updated, grants: grants.map(toDto) };
+    return { granted, updated, grants: await toDtosWithNames(tx, grants) };
   });
 }
 
@@ -236,7 +273,7 @@ export async function forceAdjustGrants(
       where: { organizationId: deps.organizationId, nodeId: node.id, revokedAt: null },
       orderBy: [{ isCreatorGrant: "desc" }, { createdAt: "asc" }],
     });
-    return { granted, updated, grants: grants.map(toDto) };
+    return { granted, updated, grants: await toDtosWithNames(tx, grants) };
   });
 }
 
diff --git a/hub/test/integration/filelib-routes.test.ts b/hub/test/integration/filelib-routes.test.ts
index b813cf9..ea2a2c5 100644
--- a/hub/test/integration/filelib-routes.test.ts
+++ b/hub/test/integration/filelib-routes.test.ts
@@ -150,6 +150,42 @@ describe("filelib http · 8.1 授权矩阵", () => {
     expect(revoke.statusCode).toBe(403);
     expect(revoke.json().error.code).toBe("cannot_touch_creator");
   });
+
+  it("grants 返回 principalName:USER→displayName / GROUP→组名;取不到行时回落为 id", async () => {
+    const rootId = await createRoot(ADMIN_COOKIE());
+    const group = await prisma.memberGroup.create({ data: { name: "物理组" } });
+
+    const put = await app.inject({
+      method: "PUT", url: `/database/api/nodes/${rootId}/grants`,
+      headers: { cookie: ADMIN_COOKIE() },
+      payload: {
+        grants: [
+          { principalType: "USER", principalId: "u_alice", role: "EDIT" },
+          { principalType: "GROUP", principalId: group.id, role: "VIEW" },
+          // 数据库里没有对应 User 行(已删/脏数据)→ 回落为 principalId
+          { principalType: "USER", principalId: "u_ghost", role: "VIEW" },
+        ],
+      },
+    });
+    expect(put.statusCode).toBe(200);
+
+    const list = await app.inject({
+      method: "GET", url: `/database/api/nodes/${rootId}/grants`,
+      headers: { cookie: ADMIN_COOKIE() },
+    });
+    expect(list.statusCode).toBe(200);
+    const byPrincipal = new Map<string, string>(
+      list.json().grants.map((g: { principalId: string; principalName: string }) => [g.principalId, g.principalName]),
+    );
+    expect(byPrincipal.get("u_alice")).toBe("Alice");
+    expect(byPrincipal.get(group.id)).toBe("物理组");
+    expect(byPrincipal.get("u_ghost")).toBe("u_ghost");
+    // 创建者授权也要解析出名字
+    const creator = list.json().grants.find((g: { isCreatorGrant: boolean }) => g.isCreatorGrant);
+    expect(creator.principalName).toBe("Admin");
+    // PUT 响应与 GET 同形状
+    expect(put.json().grants.every((g: { principalName?: string }) => typeof g.principalName === "string")).toBe(true);
+  });
 });
 
 describe("filelib http · 文件冲突流", () => {