the characteristics of development and activity of fault in the Xujiaweizi fault depression, Songliao Basin,were analyzed. The control of fault on deep gas reservoir was investigated. Five cases of fault system were developed in the Xujiaweizi fault depression, including the western Xujiaweizi early extensional strikeslip fault system, central Xujiaweizi strikeslip longterm active fault system, eastern Xujiaweizi strikeslip fault system, early extensional and later tensoshear longterm active fault system, later tensoshear fault system. Fault activity periods are fault depression period，from K1q deposition to later stage——K1qn deposition period. The Xuxi early extensional strikeslip fault system control the distribution of K1sh source rock, the Xuzhong and Xudong strikeslip fault system control the distribution of K1yc1 and K1yc3volcanic, laterterm activity fault was well vertical pathway of gas vertical migration. Fault destructiveness to K1d2 region caprock is poor, gas mainly accumulate k1yc formation in Xujiaweizi fault depression, the relationship of lithological juxtaposition was volcanic—sand shale, the fault was lateral seal, the relationship of lithological juxtaposition was volcanic—volcanic, the fault was not lateral seal, later structural reverse was poor, the damage degree of hydrocarbon by fault was poor, it was better to hydrocarbon conserve.