diff --git a/crontab.go b/crontab.go
index 842b6cf..e471def 100644
--- a/crontab.go
+++ b/crontab.go
@@ -9,7 +9,7 @@ import (
 	"strings"
 	"time"
 
-	clinked "474420502.top/eson/structure/circular_linked"
+	"474420502.top/eson/structure/circular_linked"
 	"github.com/Pallinder/go-randomdata"
 
 	"github.com/davecgh/go-spew/spew"
@@ -55,9 +55,10 @@ type Crontab struct {
 
 	YearPlan *trieYear
 
-	interval   *clinked.CircularLinked
-	lastStatus bool
-	nextTime   time.Time
+	interval     *clinked.CircularLinked
+	lastStatus   bool
+	isCalculated bool
+	nextTime     time.Time
 }
 
 // NewCrontab create 一个crontab
@@ -82,20 +83,17 @@ func (cron *Crontab) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	return nil
 }
 
-// SetStatus 设置状态 接口定义
-func (cron *Crontab) SetStatus(status interface{}) {
+// SetStatus 设置上次状态 true false
+func (cron *Crontab) SetStatus(status bool) {
 
 	if cron.interval != nil {
-		cron.lastStatus = status.(bool)
+		cron.lastStatus = status
 	}
 }
 
-// GetStatus 设置状态 接口定义
-func (cron *Crontab) GetStatus() (status interface{}) {
-	if cron.interval != nil {
-		return cron.lastStatus
-	}
-	return nil
+// GetStatus 获取上次状态 true false
+func (cron *Crontab) GetStatus() (status bool) {
+	return cron.lastStatus
 }
 
 // TimeUp 是否时间快到
@@ -111,6 +109,10 @@ func (cron *Crontab) TimeUp() bool {
 // NextTime 返回下次任务的时间
 func (cron *Crontab) NextTime() time.Time {
 	if cron.interval != nil {
+		if !cron.isCalculated {
+			now := time.Now()
+			cron.intervalCalculateNextTime(now)
+		}
 		return cron.nextTime
 	}
 
@@ -136,6 +138,7 @@ func (cron *Crontab) FromString(crontab string) error {
 		// "f1-2|5-10x5,f1|10m,10-15,f1"
 
 		cron.lastStatus = true
+		cron.isCalculated = false
 		cron.interval = clinked.NewCircularLinked()
 		var intervalList []interface{}
 		intervalList = parseIntervalString(matches[0])
@@ -214,30 +217,35 @@ func (cron *Crontab) linuxTimeUp() bool {
 	return false
 }
 
+// IntervalCalculateNextTime  计算时间间隔的下次时间
+func (cron *Crontab) intervalCalculateNextTime(now time.Time) {
+	iv := cron.interval.Cursor().GetValue().(hInterval)
+	isecond := 0
+	if cron.lastStatus == false && len(iv.PlanFail) > 0 {
+		idx := randomdata.Number(len(iv.PlanFail))
+		lr := iv.PlanFail[idx]
+		isecond = randomdata.Number(lr.left, lr.right+1)
+		log.Println("fail time ", isecond)
+	} else {
+		idx := randomdata.Number(len(iv.PlanNormal))
+		lr := iv.PlanNormal[idx]
+		isecond = randomdata.Number(lr.left, lr.right+1)
+	}
+
+	iv.Count--
+	if iv.Count <= 0 {
+		iv.reset()
+		cron.interval.MoveNext()
+	}
+	cron.nextTime = now.Add(time.Duration(isecond) * time.Second)
+}
+
 func (cron *Crontab) intervalTimeUp() bool {
 
 	now := time.Now()
+
 	if now.Unix() >= cron.nextTime.Unix() {
-
-		iv := cron.interval.Cursor().GetValue().(hInterval)
-		isecond := 0
-		if cron.lastStatus == false && len(iv.PlanFail) > 0 {
-			idx := randomdata.Number(len(iv.PlanFail))
-			lr := iv.PlanFail[idx]
-			isecond = randomdata.Number(lr.left, lr.right+1)
-		} else {
-			idx := randomdata.Number(len(iv.PlanNormal))
-			lr := iv.PlanNormal[idx]
-			isecond = randomdata.Number(lr.left, lr.right+1)
-		}
-
-		iv.Count--
-		if iv.Count <= 0 {
-			iv.reset()
-			cron.interval.MoveNext()
-		}
-
-		cron.nextTime = now.Add(time.Duration(isecond) * time.Second)
+		cron.isCalculated = false
 		return true
 	}