diff --git a/queue.go b/queue.go
deleted file mode 100644
index d9dfa12..0000000
--- a/queue.go
+++ /dev/null
@@ -1,49 +0,0 @@
-package concurrency
-
-import "sync"
-
-type Queue struct {
-	sync.Mutex
-	data []interface{}
-}
-
-func NewQueue() *Queue {
-	return &Queue{
-		data: make([]interface{}, 0),
-	}
-}
-
-func (c *Queue) Push(eles ...interface{}) {
-	c.Lock()
-	c.data = append(c.data, eles...)
-	c.Unlock()
-}
-
-func (c *Queue) Front() interface{} {
-	c.Lock()
-	defer c.Unlock()
-
-	if n := len(c.data); n == 0 {
-		return nil
-	} else {
-		var result = c.data[0]
-		c.data = c.data[1:]
-		return result
-	}
-}
-
-func (c *Queue) Len() int {
-	c.Lock()
-	length := len(c.data)
-	c.Unlock()
-	return length
-}
-
-// All 返回所有数据并清空队列
-func (c *Queue) All() []interface{} {
-	c.Lock()
-	data := c.data
-	c.data = make([]interface{}, 0)
-	c.Unlock()
-	return data
-}
diff --git a/worker_group.go b/worker_group.go
index c9b6099..e19d701 100644
--- a/worker_group.go
+++ b/worker_group.go
@@ -3,7 +3,6 @@ package concurrency
 import (
 	"github.com/hashicorp/go-multierror"
 	"sync"
-	"sync/atomic"
 )
 
 type WorkerGroup struct {
@@ -11,7 +10,7 @@ type WorkerGroup struct {
 	err       error
 	config    *Config
 	done      chan bool
-	q         *Queue
+	q         []Job
 	taskDone  int64
 	taskTotal int64
 }
@@ -25,24 +24,23 @@ func NewWorkerGroup(options ...Option) *WorkerGroup {
 	o := &WorkerGroup{
 		mu:       &sync.Mutex{},
 		config:   config.init(),
-		q:        NewQueue(),
+		q:        make([]Job, 0),
 		taskDone: 0,
 		done:     make(chan bool),
 	}
 	return o
 }
 
-// Len 获取队列中剩余任务数量
-func (c *WorkerGroup) Len() int {
-	return c.q.Len()
-}
+func (c *WorkerGroup) getJob() interface{} {
+	c.mu.Lock()
+	defer c.mu.Unlock()
 
-// AddJob 往任务队列中追加任务
-func (c *WorkerGroup) AddJob(jobs ...Job) {
-	atomic.AddInt64(&c.taskTotal, int64(len(jobs)))
-	for i, _ := range jobs {
-		c.q.Push(jobs[i])
+	if n := len(c.q); n == 0 {
+		return nil
 	}
+	var result = c.q[0]
+	c.q = c.q[1:]
+	return result
 }
 
 func (c *WorkerGroup) appendError(err error) {
@@ -54,33 +52,55 @@ func (c *WorkerGroup) appendError(err error) {
 	c.mu.Unlock()
 }
 
-func (c *WorkerGroup) do() {
-	if atomic.LoadInt64(&c.taskDone) == atomic.LoadInt64(&c.taskTotal) {
+func (c *WorkerGroup) incr(d int64) bool {
+	c.mu.Lock()
+	c.taskDone += d
+	ok := c.taskDone == c.taskTotal
+	c.mu.Unlock()
+	return ok
+}
+
+func (c *WorkerGroup) do(job Job) {
+	if !isCanceled(c.config.Context) {
+		c.appendError(c.config.Caller(job))
+	}
+	if c.incr(1) {
 		c.done <- true
 		return
 	}
-
-	if item := c.q.Front(); item != nil {
-		go func(job Job) {
-			if !isCanceled(c.config.Context) {
-				c.appendError(c.config.Caller(job))
-			}
-			atomic.AddInt64(&c.taskDone, 1)
-			c.do()
-		}(item.(Job))
+	if nextJob := c.getJob(); nextJob != nil {
+		c.do(nextJob.(Job))
 	}
 }
 
+// Len 获取队列中剩余任务数量
+func (c *WorkerGroup) Len() int {
+	c.mu.Lock()
+	x := len(c.q)
+	c.mu.Unlock()
+	return x
+}
+
+// AddJob 往任务队列中追加任务
+func (c *WorkerGroup) AddJob(jobs ...Job) {
+	c.mu.Lock()
+	c.taskTotal += int64(len(jobs))
+	c.q = append(c.q, jobs...)
+	c.mu.Unlock()
+}
+
 // StartAndWait 启动并等待所有任务执行完成
 func (c *WorkerGroup) StartAndWait() {
-	var taskTotal = atomic.LoadInt64(&c.taskTotal)
+	var taskTotal = int64(c.Len())
 	if taskTotal == 0 {
 		return
 	}
 
 	var co = min(c.config.Concurrency, taskTotal)
 	for i := int64(0); i < co; i++ {
-		c.do()
+		if item := c.getJob(); item != nil {
+			go c.do(item.(Job))
+		}
 	}
 
 	<-c.done
diff --git a/worker_queue.go b/worker_queue.go
index 53209b1..468ac27 100644
--- a/worker_queue.go
+++ b/worker_queue.go
@@ -30,18 +30,6 @@ func NewWorkerQueue(options ...Option) *WorkerQueue {
 	}
 }
 
-// AddJob 追加任务, 有资源空闲的话会立即执行
-func (c *WorkerQueue) AddJob(jobs ...Job) {
-	c.mu.Lock()
-	c.q = append(c.q, jobs...)
-	c.mu.Unlock()
-
-	var n = len(jobs)
-	for i := 0; i < n; i++ {
-		c.do()
-	}
-}
-
 func (c *WorkerQueue) getJob() interface{} {
 	c.mu.Lock()
 	defer c.mu.Unlock()
@@ -65,15 +53,13 @@ func (c *WorkerQueue) incr(d int64) {
 	c.mu.Unlock()
 }
 
-func (c *WorkerQueue) do() {
-	if item := c.getJob(); item != nil {
-		go func(job Job) {
-			if !isCanceled(c.config.Context) {
-				c.callOnError(c.config.Caller(job))
-			}
-			c.incr(-1)
-			c.do()
-		}(item.(Job))
+func (c *WorkerQueue) do(job Job) {
+	if !isCanceled(c.config.Context) {
+		c.callOnError(c.config.Caller(job))
+	}
+	c.incr(-1)
+	if nextJob := c.getJob(); nextJob != nil {
+		c.do(nextJob.(Job))
 	}
 }
 
@@ -93,6 +79,28 @@ func (c *WorkerQueue) getCurConcurrency() int64 {
 	return x
 }
 
+// Len 获取队列中剩余任务数量
+func (c *WorkerQueue) Len() int {
+	c.mu.Lock()
+	x := len(c.q)
+	c.mu.Unlock()
+	return x
+}
+
+// AddJob 追加任务, 有资源空闲的话会立即执行
+func (c *WorkerQueue) AddJob(jobs ...Job) {
+	c.mu.Lock()
+	c.q = append(c.q, jobs...)
+	c.mu.Unlock()
+
+	var n = len(jobs)
+	for i := 0; i < n; i++ {
+		if item := c.getJob(); item != nil {
+			go c.do(item.(Job))
+		}
+	}
+}
+
 // Stop 优雅退出
 // timeout 超时时间
 func (c *WorkerQueue) StopAndWait(timeout time.Duration) {