Abstract: The effectiveness of fault,the connectivity of skeletal sand body,and the impact of unconformity surface on hydrocarbon migration at the south slope area of Boxing sag are discussed.Consequently,it is concluded that there are three types of migration paths as fissure type,fault plus sand body type and sand body plus unconformity surface type.Different type of migration path occurs in different structural zone, thus dominating the generation of different type of oil and gas pool.The fissure type of migration path is distributed in the northwest of the sag;the fault plus sand body type is the primary migration path in the slope;and the sand body plus unconformity type is near the outside zone of the south slope.