The stability of landslides under the coupling action of earthquake and rainfall is ana- lyzed with an example of No. Ⅲ landslide of Xihe county, Gansu province. We adopte Geostudio software to simulate the landslide in two conditions, i.e. natural status and the coupling influence from earthquake and rainfall. The analysis result shows that the landslide is generally stable in nature state; on the contrary, the coupling action could have serious impact on the stability of NO. Ⅲ landslide of Xihe county. The result also shows that with same calculation condition and rainfall, a certain magnitude earthquake coupling with three kinds of rainfall intensities could cause different landslide possibilities; the less rainfall intensity may cause the more reduction of the landslide stability, due to a more volume of infiltration water and a wider distributional zone of exceeding pore pressure associated with earthquake.