Abstract: It is liable to cause tensile cracking and settlement at slope during excavation of metro station under the influence of various factors, resulting in adverse effect on slope stability. A calculation equation for safety factor of cracking slope under the effect of overloaded slope top and earthquake was deduced by logarithmic spiral failure mode based on upper limit method, the optimal solutions for safety factors under different parameter combinations were obtained by using MATLAB numerical solution software, and the effect of overloaded slope top on slope stability in condition of different parameters was analyzed. The results show that the safety factors decrease with an increase of overload and the decrease rate of safety factor is relatively large when overload is small; the effect of slope angle, horizontal seismic factor, internal friction angle and cohesion factor on slope stability is significant under certain overload.