The influence of easterly wave on typhoon Knotty track is discussed the result shows that there are two cases of this influence:one is that typhoon formed in the easterly wave,the other is that easterly wave moved westward and mixed with the typhoon (or tropical storm) in its southern part. These will cause typhoon track to deviate from its normal dominating air current and move northward, then pass through subtropical high, thus typhoon Knotty track appears. The reasons of forming this kind of knotty track are analysed.