diff --git a/packages/plugin-common/src/contextify.ts b/packages/plugin-common/src/contextify.ts
index 40624a1b97..9e9954853a 100644
--- a/packages/plugin-common/src/contextify.ts
+++ b/packages/plugin-common/src/contextify.ts
@@ -1,4 +1,4 @@
-import { Context } from 'koishi-core'
+import { Context, getTargetId } from 'koishi-core'
 
 export default function apply (ctx: Context) {
   ctx.command('contextify <message...>', '在特定上下文中触发指令', { authority: 3 })
@@ -31,7 +31,8 @@ export default function apply (ctx: Context) {
       const newMeta = { ...meta }
       let user = meta.$user
       if (options.user) {
-        const id = +options.user
+        const id = getTargetId(options.user)
+        if (!id) return meta.$send('未指定目标。')
         user = await ctx.database.observeUser(id)
         if (meta.$user.authority <= user.authority) {
           return meta.$send('权限不足。')
diff --git a/packages/plugin-common/tests/contextify.spec.ts b/packages/plugin-common/tests/contextify.spec.ts
index 930c440a07..cc04392b2a 100644
--- a/packages/plugin-common/tests/contextify.spec.ts
+++ b/packages/plugin-common/tests/contextify.spec.ts
@@ -22,6 +22,7 @@ beforeAll(async () => {
 
 test('check input', async () => {
   await session1.shouldHaveReply('ctxf -u 456', '请输入要发送的文本。')
+  await session2.shouldHaveReply('ctxf -m foo show-context', '未指定目标。')
   await session1.shouldHaveReply('ctxf show-context', '请提供新的上下文。')
   await session1.shouldHaveReply('ctxf -u 789 show-context', '权限不足。')
   await session1.shouldHaveReply('ctxf -m 456 show-context', '无法在私聊上下文使用 --member 选项。')