Abstract: The reverse fault in western Qaidam basin can be divided into three radical types as contemporaneous reverse fault, epigenetic-con-temporaneous reverse fault and contemporaneous fault. The long-term activity of contemporaneous controls the deposits apparenly,forming good reservoir and caprock. The development of these reverse faults underwent the contemporaneous, epigenetic and contemporaneous stages. The earlier development and long-term activities of contemporaneous reverse faults allow petroleum in this area to be in long-term migration, ac-cumulation and enrichment, not only as vertical passages for migration, but also as lateral connection channels between the reservoir and the source rock.

Key words: Qaidam basin, reverse fault, contemporaneous fault, petroleum migration, petroleum accumulation