Abstract: 3DVSP common detection point gathers produce different tensile distortion effects at different offsets after conventional processing,especially at the shallow layer and large offset,which affects the imaging quality of the superimposed section.In view of such a situation,the author analyzed the stretch effect reason,deduced the stretch rate formula,and proposed a trace-set cutting method based on stretch rate:to calculate the stretch rate of each point in the trace set of common detection points point by point,determine the range of effective stretch rate,and cut the points with excessive stretch rate.The results of model analysis and actual data processing show that the method is correct and effective.