Abstract: Based on the model test data, presenting the soil shear strength parameters and precipitation infiltration time as a function of the moisture content, modifying the simplified Bishop calculation model make it being able to reflect the phenomenon that the strength of the soil mass would be reduced by the change in the moisture content of the slope soil mass. With the aid of Fortran program, a program which is coupling saturated-unsaturated seepage finite element method and limit equilibrium slope stability (a corrected simplified Bishop method) is developed in this study. The program takes into account the slope soil shear strength parameters changed along with the development of precipitation infiltration, using saturated-unsaturated seepage for calculating variation and expansion process of the moisture content of the slope soil mass during rainfall. Through physical model tests, slope seepage in the development process and the process of change in the slope safety degree under the rainfall conditions have been calculated and analyzed. And the calculated results are good in agreement with the experimental research results, which differs by about 35% from the slope safety factor given by the simplified Bishop method before correction. This corrected simplified calculation method for slope stability will provide a new useful reference for the calculation of precipitation induced landslides.