diff --git a/core/common/page/page.go b/core/common/page/page.go
index 8853a1b..cc68513 100644
--- a/core/common/page/page.go
+++ b/core/common/page/page.go
@@ -8,6 +8,7 @@ import (
     "github.com/hu17889/go_spider/core/common/page_items"
     "github.com/hu17889/go_spider/core/common/request"
     "net/http"
+    //"fmt"
 )
 
 // Page represents an entity be crawled.
diff --git a/core/common/util/util.go b/core/common/util/util.go
index cf86bcb..79ca0f7 100644
--- a/core/common/util/util.go
+++ b/core/common/util/util.go
@@ -20,6 +20,7 @@ func JsonpToJson(json string) string {
     if end > start && end != -1 && start != -1 {
         json = json[start : end+1]
     }
+    json = strings.Replace(json, "\\'", "", -1)
     regDetail, _ := regexp.Compile("([^\\s\\:\\{\\,\\d\"]+|[a-z][a-z\\d]*)\\s*\\:")
     return regDetail.ReplaceAllString(json, "\"$1\":")
 }
diff --git a/core/downloader/downloader_http.go b/core/downloader/downloader_http.go
index 3535b48..437816c 100644
--- a/core/downloader/downloader_http.go
+++ b/core/downloader/downloader_http.go
@@ -186,7 +186,7 @@ func (this *HttpDownloader) downloadJson(p *page.Page, req *request.Request) *pa
 
     var r *simplejson.Json
     if r, err = simplejson.NewJson(body); err != nil {
-        mlog.LogInst().LogError(err.Error())
+        mlog.LogInst().LogError(string(body) + "\t" + err.Error())
         p.SetStatus(true, err.Error())
         return p
     }
diff --git a/core/scheduler/scheduler_queue.go b/core/scheduler/scheduler_queue.go
index 26552f8..dc28d8b 100644
--- a/core/scheduler/scheduler_queue.go
+++ b/core/scheduler/scheduler_queue.go
@@ -6,30 +6,64 @@
 package scheduler
 
 import (
+    "container/list"
+    "crypto/md5"
     "github.com/hu17889/go_spider/core/common/request"
+    "sync"
+    //"fmt"
 )
 
 type QueueScheduler struct {
-    queue chan *request.Request
+    locker *sync.Mutex
+    rm     bool
+    rmKey  map[[md5.Size]byte]*list.Element
+    queue  *list.List
 }
 
-func NewQueueScheduler() *QueueScheduler {
-    ch := make(chan *request.Request, 1024)
-    return &QueueScheduler{ch}
+func NewQueueScheduler(rmDuplicate bool) *QueueScheduler {
+    queue := list.New()
+    rmKey := make(map[[md5.Size]byte]*list.Element)
+    locker := new(sync.Mutex)
+    return &QueueScheduler{rm: rmDuplicate, queue: queue, rmKey: rmKey, locker: locker}
 }
 
 func (this *QueueScheduler) Push(requ *request.Request) {
-    this.queue <- requ
+    this.locker.Lock()
+    var key [md5.Size]byte
+    if this.rm {
+        key = md5.Sum([]byte(requ.GetUrl()))
+        if _, ok := this.rmKey[key]; ok {
+            this.locker.Unlock()
+            return
+        }
+    }
+    e := this.queue.PushBack(requ)
+    if this.rm {
+        this.rmKey[key] = e
+    }
+    this.locker.Unlock()
 }
 
 func (this *QueueScheduler) Poll() *request.Request {
-    if len(this.queue) == 0 {
+    this.locker.Lock()
+    if this.queue.Len() <= 0 {
+        this.locker.Unlock()
         return nil
-    } else {
-        return <-this.queue
     }
+    e := this.queue.Front()
+    requ := e.Value.(*request.Request)
+    key := md5.Sum([]byte(requ.GetUrl()))
+    this.queue.Remove(e)
+    if this.rm {
+        delete(this.rmKey, key)
+    }
+    this.locker.Unlock()
+    return requ
 }
 
 func (this *QueueScheduler) Count() int {
-    return len(this.queue)
+    this.locker.Lock()
+    len := this.queue.Len()
+    this.locker.Unlock()
+    return len
 }
diff --git a/core/scheduler/scheduler_test.go b/core/scheduler/scheduler_test.go
index 5bec640..318aa6d 100644
--- a/core/scheduler/scheduler_test.go
+++ b/core/scheduler/scheduler_test.go
@@ -15,15 +15,46 @@ import (
 func TestQueueScheduler(t *testing.T) {
     var r *request.Request
     r = request.NewRequest("http://baidu.com", "html")
+    fmt.Printf("%v\n", r)
 
     var s *scheduler.QueueScheduler
-    s = scheduler.NewQueueScheduler()
+    s = scheduler.NewQueueScheduler(false)
 
     s.Push(r)
     var count int = s.Count()
+    if count != 1 {
+        t.Error("count error")
+    }
     fmt.Println(count)
 
     var r1 *request.Request
     r1 = s.Poll()
-    fmt.Println(r1)
+    if r1 == nil {
+        t.Error("poll error")
+    }
+    fmt.Printf("%v\n", r1)
+
+    // remove duplicate
+    s = scheduler.NewQueueScheduler(true)
+
+    r2 := request.NewRequest("http://qq.com", "html")
+    s.Push(r)
+    s.Push(r2)
+    s.Push(r)
+    count = s.Count()
+    if count != 2 {
+        t.Error("count error")
+    }
+    fmt.Println(count)
+
+    r1 = s.Poll()
+    if r1 == nil {
+        t.Error("poll error")
+    }
+    fmt.Printf("%v\n", r1)
+    r1 = s.Poll()
+    if r1 == nil {
+        t.Error("poll error")
+    }
+    fmt.Printf("%v\n", r1)
 }
diff --git a/core/spider/spider.go b/core/spider/spider.go
index 0781024..da929c5 100644
--- a/core/spider/spider.go
+++ b/core/spider/spider.go
@@ -13,6 +13,7 @@ import (
     "github.com/hu17889/go_spider/core/scheduler"
     "math/rand"
     "time"
+    //"fmt"
 )
 
 type Spider struct {
@@ -53,7 +54,7 @@ func NewSpider(pageinst page_processer.PageProcesser, taskname string) *Spider {
 
     // init spider
     if ap.pScheduler == nil {
-        ap.SetScheduler(scheduler.NewQueueScheduler())
+        ap.SetScheduler(scheduler.NewQueueScheduler(false))
     }
 
     if ap.pDownloader == nil {
@@ -128,7 +129,7 @@ func (this *Spider) Run() {
 }
 
 func (this *Spider) close() {
-    this.SetScheduler(scheduler.NewQueueScheduler())
+    this.SetScheduler(scheduler.NewQueueScheduler(false))
     this.SetDownloader(downloader.NewHttpDownloader())
     this.pPiplelines = make([]pipeline.Pipeline, 0)
     this.exitWhenComplete = true
@@ -272,6 +273,7 @@ func (this *Spider) pageProcess(req *request.Request) {
 
     this.pPageProcesser.Process(p)
     for _, req := range p.GetTargetRequests() {
+        //fmt.Printf("%v\n",req)
         this.addRequest(req)
     }