Abstract We use the sequence stratigraphy paleogeomorphology restoration method to restore the original paleogeomorphology of the three key interfaces of the paleogene Liushagang formation in Fushan sag of Beibuwan basin by calculating the basin subsidence. The simulation results show that the geomorphic gullies are developed vertically and horizontally, and the depressions are highly segmented. In the vertical direction, from Els3 to Els1 period, the paleogeomorphic undulation is obviously episodic, and the eastern and western depressions presents distinctive subsidence characteristics and structural patterns.