In the mining process of open-pit stope,geological conditions are gradually revealed,so a single slope design and construction parameter can not adapt to the complex engineering geological conditions.Therefore,it is necessary to carry out engineering geological zoning,and reasonable optimization of slope parameters.Taking a large open-pit mine as the research object,the exposed strata were pided,and at the same time,the site structural plane investigation and analysis were carried out to establish a complete geological model.According to the different influencing factors,the stope was pided into engineering geological zones,and the typical section was selected to analyze the failure mode on the basis of each geological zone.The rock soil strength parameters were determined by laboratory test and engineering analogy method.According to the overall stability of slope and the local stability of step slope,back analysis for the strength parameters of alluvial layer,limestone,limestone fracture zone and porphyry fracture zone respectively was carried out,and the recommended value of rock soil strength parameters of open-pit stope slope was given.