diff --git a/bin/dbVersion.json b/bin/dbVersion.json
index c580866..f483ccf 100644
--- a/bin/dbVersion.json
+++ b/bin/dbVersion.json
@@ -16,7 +16,8 @@
     {"file": "20180811-1.sql", "version": 14},
     {"file": "20180815-1.sql", "version": 15},
     {"file": "20180816-1.sql", "version": 16},
-    {"file": "20180826-1.sql", "version": 17}
+    {"file": "20180826-1.sql", "version": 17},
+    {"file": "20180828-1.sql", "version": 18}
   ],
   "test": []
 }
\ No newline at end of file
diff --git a/libs/api-action/line.js b/libs/api-action/line.js
index 16f4883..4f36a71 100644
--- a/libs/api-action/line.js
+++ b/libs/api-action/line.js
@@ -95,7 +95,37 @@ const replyMessage = async (replyToken, message) => {
   }
 }
 
+/**
+ * query user info
+ * @param {string} group group id
+ * @param {string} id user id
+ */
+const getUserInfo = async (group = '', id = '') => {
+  if (typeof group !== 'string' || group.trim().length === 0) return null
+  if (typeof id !== 'string' || id.trim().length === 0) return null
+  let url = `/group/${group.trim()}/member/${id.trim()}`
+  try {
+    let result = await client({
+      url,
+      method: 'get'
+    })
+    if ('data' in result && typeof result.data === 'object') {
+      let {displayName, userId} = result.data
+      if (typeof displayName !== 'string' || displayName.length === 0) return null
+      if (typeof userId !== 'string' || userId.length === 0) return null
+      return {
+        displayName,
+        userId
+      }
+    }
+  } catch (err) {
+    console.log('get user info error :::: ', err)
+  }
+  return null
+}
+
 module.exports = {
   pushMessage,
-  replyMessage
+  replyMessage,
+  getUserInfo
 }
diff --git a/libs/line-message/index.js b/libs/line-message/index.js
index 22254b9..4757c81 100644
--- a/libs/line-message/index.js
+++ b/libs/line-message/index.js
@@ -23,6 +23,10 @@ const textMessage = async (evt) => {
   text = text.trim()
   if (text.length === 0) return
 
+  saveToLog(source, text).then(() => {}).catch(err => {
+    console.log(err)
+  })
+
   let result = await commands(text, source)
   if (result === null) return
   if (typeof result === 'object' && 'reply' in result) {
@@ -31,6 +35,41 @@ const textMessage = async (evt) => {
   }
 }
 
+const saveToLog = async (source, text = '') => {
+  if (!source || typeof source !== 'object') return null
+  if (typeof text !== 'string' || text.length === 0) return null
+  let {groupId, userId} = source
+  if (typeof groupId !== 'string' || groupId.length === 0) return null
+  if (typeof userId !== 'string' || userId.length === 0) return null
+  // connect database
+  let db = await DB.connect()
+
+  try {
+    let text = `select * from "public"."line_user" where "id" = $1`
+    let values = [userId]
+    let user = await db.query({text, values})
+    let data = null
+    if (user.rowCount === 0) {
+      data = api.line.getUserInfo(groupId, userId)
+      if (data === null) {
+        db.release()
+        return null
+      }
+      let text = `insert into "public"."line_user" ("id", "name") values ($1, $2)`
+      let values = [userId, data.displayName]
+      await db.query({text, values})
+    }
+    text = `insert into "public"."line_message_log" ("group", "user", "message") values ($1, $2, $3)`
+    values = [groupId, userId, text]
+    await db.query({text, values})
+  } catch (err) {
+    console.log('save log error :::: ', err)
+  }
+
+  db.release()
+  return null
+}
+
 const leaveGroup = async (group = '') => {
   if (typeof group !== 'string' || group.trim().length === 0) return
   let db = await DB.connect()
diff --git a/schema/20180828-1.sql b/schema/20180828-1.sql
new file mode 100644
index 0000000..d26f0cf
--- /dev/null
+++ b/schema/20180828-1.sql
@@ -0,0 +1,21 @@
+CREATE TABLE public.line_user
+(
+    id varchar(256) PRIMARY KEY NOT NULL,
+    name varchar(512) NOT NULL,
+    ctime timestamp with time zone DEFAULT current_timestamp NOT NULL,
+    mtime timestamp with time zone DEFAULT current_timestamp NOT NULL
+);
+
+CREATE TABLE public.line_message_log
+(
+    "group" varchar(256) NOT NULL,
+    "user" varchar(256) NOT NULL,
+    message varchar(2048) DEFAULT '' NOT NULL,
+    ctime timestamp with time zone DEFAULT current_timestamp NOT NULL,
+    mtime timestamp with time zone DEFAULT current_timestamp NOT NULL,
+    CONSTRAINT line_message_log_line_group_id_fk FOREIGN KEY ("group") REFERENCES public.line_group (id) ON DELETE CASCADE,
+    CONSTRAINT line_message_log_line_user_id_fk FOREIGN KEY ("user") REFERENCES public.line_user (id) ON DELETE CASCADE
+);
+
+ALTER TABLE public.line_message_log ADD id uuid DEFAULT public.uuid_generate_v4() NOT NULL;
+ALTER TABLE public.line_message_log ADD CONSTRAINT line_message_log_pk PRIMARY KEY (id);
\ No newline at end of file