Abstract: This paper defines the levels and categories of slope break zones,perfects the division of scale,and studies the evolution history based on the tectonic cycle and the distributive regularities of sedimentary facies so that the control action of slope break zones to sedimentary system can be depicted dynamically. The study shows that the slope break zones can be classified into first-order slope break zones,second -order slope break zones and third-order slope break zones according to their size,and their genetic types can be divided into fault slope break zones and erodent slope break zones. The first-order slope break zones showing S type throughout south-north are rich in north area and less in south area,and the least in the middle area. The development of slope break zones are controlled by the activities of Xihu sag and the south-north evolution of slope break zones are different. The distribution range of delta facies controlled by the slope break zones in Pingbei district is smaller than Pingnan district. Consequently it is obvious that the study of slope break zone in Pinghu slope zone around Xihu Sag of East China Sea shows important theoretical value and operation significance for petroleum exploration in this area.