Abstract: To evaluate the effects of check dams on slope stability, slope stability model based on GIS was adopted in this study. According to the measured soil mechanics parameters and the data of field survey to landslide sites, the slope stability with the check dam deposited to different siltation heights were analyzed. The results showed that the defended slope zone was decreased and the stable slope zone was increased with the increasing of the siltation heights of check dams. The percentage of steep slope area (≥45°) was decreased with the increasing of the siltation heights, and exhibited a linear relationship with the defended slope zone. The "flooding effect" was summarized in the deposition process of check dams. Sediment deposition not only changed the valley slope constitution and shortened the slope length, but also changed the cover-manegement factors and support practice factors. The study provides a reference for check dams building.