Abstract: The slope zone of Biyang depression developed many faults and has complicated faults system. This paper pointed out that main fault’s scale and continuity and arrangement relationship with sand-body distribution and axial direction of the nose structure control the hydrocarbon migration and pool type and accumulation and enrich-ment through studying on feature of faults system and hydrocarbon accumulation in slope zone of Biyang depression. The second hydro-carbon Exploration is very successful based on these study.

Key words: Biyang depression, nose structure, main frac-ture, faults system