Because of absorption of the basement fault strain by the loose cover，the latestage faults developed in the basin with the duplex of basement and unconsolidated cover，are characterized by intense deformation in the lower layers while weak deformation in the upper layers，which we call reverse grading faults in this paper. When the basement faults are strikeslip faults，they would also have the spatial duplex feature，with main strikeslip faults developed in the basement and secondary echelon faults in other trend in the cover deposition. These reverse strikeslip faults have been widely distributed in the Bohai gulf basin. By 3D seismic reflection data，this paper would take the Zhangbei and Baishuitou fault zones(both developed with NE main basement faults in lower layers and EW secondary cover faults in upper layers)as examples，to describes such development characteristics and identification features from the seismic reflection profiles of these reverse grading faults. As reverse grading faults used to be treated as contemporaneous growth faults，this paper would help to bring new interpretation of the regional fault structure and tectonic evolution.