Fault sealing evolution is analyzed based on the normal stress calculation of Dainan Formation reservoir. The favorable area of fault-lithologic reservoirs is predicted in Gaoyou Depression of Subei Basin. It is concluded that the present normal stress of major faults in fauh-lithologic reservoirs is from 13.8 to 25 MPa and the critieal value of fauh sealing is 13.8 MPa. The normal stress of fauhs in fauh-lithologic reservoirs in accumulation period is from 8.9 to 20.2 MPa, most of tile reservoir faults are open in the accumulation period, but they are closed now. However, there is one reservoir with fault sealing all the time, which is Shaoshen I reservoir thought to be the own source type.