diff --git a/next/api/src/controller/ticket.ts b/next/api/src/controller/ticket.ts
index 803cedc2b..8926dd79f 100644
--- a/next/api/src/controller/ticket.ts
+++ b/next/api/src/controller/ticket.ts
@@ -6,19 +6,23 @@ import {
   Body,
   Controller,
   Ctx,
+  CurrentUser,
   Delete,
   Get,
   Param,
   Post,
+  Query,
   ResponseBody,
   UseMiddlewares,
 } from '@/common/http';
-import { ZodValidationPipe } from '@/common/pipe';
+import { ParseBoolPipe, ZodValidationPipe } from '@/common/pipe';
 import { customerServiceOnly, staffOnly } from '@/middleware';
 import { UpdateData } from '@/orm';
 import router from '@/router/ticket';
 import { Ticket } from '@/model/Ticket';
 import { TicketListItemResponse } from '@/response/ticket';
+import { User } from '@/model/User';
+import { redis } from '@/cache';
 
 const createAssociatedTicketSchema = z.object({
   ticketId: z.string(),
@@ -106,4 +110,27 @@ export class TicketController {
 
     await Ticket.updateSome(updatePairs, { useMasterKey: true });
   }
+
+  // The :id is not used to avoid fetch ticket data by router.param
+  // This API may be called frequently, and we do not care if the ticket exists
+  @Get(':roomId/viewers')
+  @UseMiddlewares(staffOnly)
+  async getTicketViewers(
+    @Param('roomId') id: string,
+    @Query('excludeSelf', ParseBoolPipe) excludeSelf: boolean,
+    @CurrentUser() user: User
+  ) {
+    const key = `ticket_viewers:${id}`;
+    const now = Date.now();
+    const results = await redis
+      .pipeline()
+      .zadd(key, now, user.id) // add current user to viewer set
+      .expire(key, 100) // set ttl to 100 seconds
+      .zremrangebyrank(key, 100, -1) // keep viewer set small
+      .zremrangebyscore(key, '-inf', now - 1000 * 60) // remove viewers active 60 seconds ago
+      .zrevrange(key, 0, -1) // get all viewers
+      .exec();
+    const viewers: string[] = _.last(results)?.[1] || [];
+    return excludeSelf ? viewers.filter((id) => id !== user.id) : viewers;
+  }
 }
diff --git a/next/web/src/App/Admin/Tickets/Ticket/TicketDetail.tsx b/next/web/src/App/Admin/Tickets/Ticket/TicketDetail.tsx
index 76c2cc2da..7cebd3180 100644
--- a/next/web/src/App/Admin/Tickets/Ticket/TicketDetail.tsx
+++ b/next/web/src/App/Admin/Tickets/Ticket/TicketDetail.tsx
@@ -57,6 +57,7 @@ import { CustomFields } from './components/CustomFields';
 import { useTicketOpsLogs, useTicketReplies } from './timeline-data';
 import { RecentTickets } from './components/RecentTickets';
 import { Evaluation } from './components/Evaluation';
+import { TicketViewers } from './components/TicketViewers';
 
 export function TicketDetail() {
   const { id } = useParams() as { id: string };
@@ -191,6 +192,7 @@ export function TicketDetail() {
 
 interface TicketInfoProps {
   ticket: {
+    id: string;
     nid: number;
     title: string;
     status: number;
@@ -225,6 +227,7 @@ function TicketInfo({
       }
       onBack={onBack}
       extra={[
+        <TicketViewers key="viewers" ticket={ticket} />,
         <PrivateSelect
           key="private"
           value={ticket.private}
diff --git a/next/web/src/App/Admin/Tickets/Ticket/components/TicketViewers.tsx b/next/web/src/App/Admin/Tickets/Ticket/components/TicketViewers.tsx
new file mode 100644
index 000000000..242b2ce99
--- /dev/null
+++ b/next/web/src/App/Admin/Tickets/Ticket/components/TicketViewers.tsx
@@ -0,0 +1,22 @@
+import { Avatar, Tooltip } from 'antd';
+
+import { UseTicketViewersOptions, useTicketViewers } from '../hooks/useTicketViewers';
+
+interface TicketViewersProps {
+  ticket: UseTicketViewersOptions;
+}
+
+export function TicketViewers({ ticket }: TicketViewersProps) {
+  const viewers = useTicketViewers(ticket);
+  return (
+    <Avatar.Group maxCount={4} style={{ display: 'flex' }}>
+      {viewers?.map((viewer) => (
+        <Tooltip key={viewer.id} title={viewer.nickname}>
+          <Avatar style={{ backgroundColor: '#' + viewer.id.slice(-12, -6) }}>
+            {viewer.nickname.slice(0, 1)}
+          </Avatar>
+        </Tooltip>
+      ))}
+    </Avatar.Group>
+  );
+}
diff --git a/next/web/src/App/Admin/Tickets/Ticket/hooks/useTicketViewers.ts b/next/web/src/App/Admin/Tickets/Ticket/hooks/useTicketViewers.ts
new file mode 100644
index 000000000..cf4b08d59
--- /dev/null
+++ b/next/web/src/App/Admin/Tickets/Ticket/hooks/useTicketViewers.ts
@@ -0,0 +1,55 @@
+import { useMemo } from 'react';
+import { useQuery } from 'react-query';
+import moment from 'moment';
+import _ from 'lodash';
+
+import { http } from '@/leancloud';
+import { useUsers } from '@/api/user';
+
+export interface UseTicketViewersOptions {
+  id: string;
+  createdAt: string;
+}
+
+export function useTicketViewers(ticket: UseTicketViewersOptions) {
+  const refetchInterval = useMemo(() => {
+    const hours = moment().diff(ticket.createdAt, 'hour');
+    if (hours < 1) {
+      // 1 小时内创建的工单每 10 秒刷新一次
+      return 10000;
+    }
+    // 增加刷新时间, 上限为 24 小时 / 40 秒
+    return Math.floor(30000 * (Math.min(24, hours) / 24)) + 10000;
+  }, [ticket.createdAt]);
+
+  const { data: viewerIds } = useQuery({
+    queryKey: ['TicketViewers', ticket.id],
+    queryFn: async () => {
+      const res = await http.get<string[]>(`/api/2/tickets/${ticket.id}/viewers`, {
+        params: { excludeSelf: 1 },
+      });
+      return res.data;
+    },
+    cacheTime: 0,
+    refetchInterval,
+    keepPreviousData: true,
+  });
+
+  const sortedIds = useMemo(() => (viewerIds || []).slice().sort(), [viewerIds]);
+
+  const { data: viewers } = useUsers({
+    id: sortedIds,
+    queryOptions: {
+      enabled: sortedIds.length > 0,
+      keepPreviousData: true,
+    },
+  });
+
+  return useMemo(() => {
+    if (viewerIds && viewers) {
+      const viewerMap = _.keyBy(viewers, (v) => v.id);
+      return viewerIds.map((id) => viewerMap[id]).filter(Boolean);
+    }
+    return [];
+  }, [viewerIds, viewers]);
+}