Abstract: The dump slope in Anqian mine is different from common slope，where its shape is complex，the gravel and soil are mixed，and the distribution is not uniform.The parameters of soil weight，cohesion and internal friction angle show larger spatial variability，and soft layer exist in the slope.These parameters are basically satisfied with the normal distribution，and its probability parameters and probability distribution are given through experiments and field statistics.With the Bishop method，three kinds of stability coefficient were calculated，that is，minimum stability coefficient without condition，minimum stability coefficient when sliding block reaching a certain scale，stability coefficient when sliding surface passing through weak plane respectively.The probability distribution of the stability coefficient is obtained by Monte Carlo Method.These probability distribution functions of stability coefficient are calculated about three representative sections and three kinds of stability coefficients.Their reliability was analyzed，and the related warning level was given.

Key words: Dump slope, Stability coefficient, Reliability, Bishop method, Monte-Carlo method