Abstract: With the high and steep rock slope of open pit in Changba Pb-Zn Mine as the background，and on the basis of the orthogonal experiments on the design variables of rock parameters，the functional relationship between the parameters of the rock mass and the calculated displacements of the slope was established through the regression analysis by using the method of least squares.Then，taking the minimum sum of squares of difference between the measured displacement and the calculated displacement as the optimal goal，the equivalent parameter of rock slope corresponds to the status of monitoring phase was determined by the means of on-site monitoring information.On this basis，the research on high and steep slope stability in the state of dry and rainfall conditions were carried out respectively by numerical simulation method，obtaining that the result conformed to the current slope condition.The results showed that the slope stability is sensitive to rainfall infiltration that becomes the main controlling factor of the slope stability.This research approach provides the basis for the dynamic prediction of high and steep rock slope stability in different mining conditions.

Key words: Equivalent model of rock mass, High and steep slope, Orthogonal experiment, Regression analysis, Numerical simulation