Abstract: To research the impacts of fault angle on the slope of dip bedded slope in surface mines, with eastern slope in Yuanbaoshan Surface Coal Mine as the engineering background, FLAC3D is used to simulate the F1 fault ,the sliding mode and the stability of the slope are compared under different inclinations. It is shown that the stability of the eastern slope in Yuanbaoshan Surface Mine is primarily controlled by the 4th weak layer and the angle of fault F1 is one of the important parameters which influence the stability of slope, that when the angle of fault F1 is more than 45° and less than 60°, the eastern slope stability of Yuanbaoshan Surface Coal Mine must increase linearly with its increase and that when the angle of fault F1 is greater than or equal to 65°, the slope failure mode and stability is no longer affected by fault F1.