Abstract: Bai zhang reservoir built in 1958 is a monotone dam. Its slope has been renovated eight times, and the gradient has been lower range from 1:2.0 to 1:5.0. In spite of this, the phenomena of the crack landslide still exist. By introducing and analyzing several situations of the landslide and treatment, this paper considers that the reason of this situation is that dam materials were designed improperly and the treatment for the size of dam slope by traditional at the beginning was unsuitably. Therefore, the quality of dam material should be firstly analyzed, and the best alternative method is to replace the landslide mass with well-graded and high shear-strength earth materials. This method is deserved deep exploration and used for reference.?