Abstract: Fushan Depression is a halfgraben-like depression in the south slope of Beibuwan Basin. More and more oil discovery is obtained these years. Oil generation, migration, accumulation and preservation are studied in this paper using theory of petroleum system. There is a set of system named Liushagang Formation Petroleum System. It is bounded by fault on the east, west and north, and on the south is bounded by erosion of 2nd member of Liushagang Formation(E₂l₂). We indicate that structural belt and fault zone around Bailian subdepression is the main exploration trend. E₂l₃¹ reservoire and E₂l₂ sealed assemblage of Liushagang Formation is the most exploration potential.