diff --git a/examples/config.mongodb b/examples/config.mongodb
new file mode 100644
index 00000000..6413b57d
--- /dev/null
+++ b/examples/config.mongodb
@@ -0,0 +1,11 @@
+root = "./"
+thread = 8
+logger = nil
+harbor = 0
+start = "main_mongodb"	-- main script
+bootstrap = "snlua bootstrap"	-- The service for bootstrap
+luaservice = root.."service/?.lua;"..root.."test/?.lua;"..root.."examples/?.lua"
+lualoader = "lualib/loader.lua"
+snax = root.."examples/?.lua;"..root.."test/?.lua"
+cpath = root.."cservice/?.so"
+-- daemon = "./skynet.pid"
diff --git a/examples/main_mongodb.lua b/examples/main_mongodb.lua
new file mode 100644
index 00000000..0f505ce6
--- /dev/null
+++ b/examples/main_mongodb.lua
@@ -0,0 +1,12 @@
+local skynet = require "skynet"
+
+
+skynet.start(function()
+	print("Main Server start")
+	local console = skynet.newservice(
+		"testmongodb", "127.0.0.1", 27017, "testdb", "test", "test"
+	)
+	
+	print("Main Server exit")
+	skynet.exit()
+end)
diff --git a/lualib/skynet/db/mongo.lua b/lualib/skynet/db/mongo.lua
index ec8063a6..e020ebcb 100644
--- a/lualib/skynet/db/mongo.lua
+++ b/lualib/skynet/db/mongo.lua
@@ -309,7 +309,7 @@ end
 
 function mongo_db:auth(user, pass)
 	local authmod = rawget(self.connection, "authmod") or "scram_sha1"
-	local auth_func = auth_method[authmod]
+	local auth_func = auth_method["auth_" .. authmod]
 	assert(auth_func , "Invalid authmod")
 	return auth_func(self, user, pass)
 end
diff --git a/test/testmongodb.lua b/test/testmongodb.lua
index 11d819be..cda41ec4 100644
--- a/test/testmongodb.lua
+++ b/test/testmongodb.lua
@@ -3,6 +3,11 @@ local mongo = require "skynet.db.mongo"
 local bson = require "bson"
 
 local host, port, db_name, username, password = ...
+if port then
+	port = math.tointeger(port)
+end
+
+-- print(host, port, db_name, username, password)
 
 local function _create_client()
 	return mongo.client(
@@ -14,6 +19,25 @@ local function _create_client()
 	)
 end
 
+function test_auth()
+	local c = mongo.client(
+		{
+			host = host, port = port,
+		}
+	)
+	db = c[db_name]
+	db:auth(username, password)
+
+	db.testdb:dropIndex("*")
+	db.testdb:drop()
+
+	local ok, err, ret = db.testdb:safe_insert({test_key = 1});
+	assert(ok and ret and ret.n == 1, err)
+
+	local ok, err, ret = db.testdb:safe_insert({test_key = 1});
+	assert(ok and ret and ret.n == 1, err)
+end
+
 function test_insert_without_index()
 	local db = _create_client()
 	db[db_name].testdb:dropIndex("*")
@@ -105,6 +129,10 @@ function test_expire_index()
 end
 
 skynet.start(function()
+	if username then
+		print("Test auth")
+		test_auth()
+	end
 	print("Test insert without index")
 	test_insert_without_index()
 	print("Test insert index")