Abstract: The accuracy of the slope stability analysis in surface mine by Bishop method was improved．Based on the study of the numerical solution for circular sliding，a method of searching for the most dangerous sliding surface is given，which is analyzed and proved more reasonable in theory．And the moving trace of circle center as the length of radius progressive increases in presupposed step length is modified．At the same time the accurate variation range of radius and the distance of fissure is derived，which also shows the relationship between the slope angle and height．When the cohesion，the internal friction angle and the density of various rock layers are confirmed the influence of the layer structure is considered，which is more practical．We put forward the program implementation of calculating the stability coefficient of circular arc sliding and the finale slope angle in surface mine slope，including the situations of searching for the most dangerous sliding surface and the slope of layer structure，and the program algorithm flow is introduced．We designed the VB program of calculating the stability coefficient and the finale slope angle in surface mine slope，of which the result is acceptable，and we can check the stability coefficient in different slope angles．

Key words: surface mine slope, Bishop approach, dangerous sliding surface, layer structure, programming