Based on the routine circular slip surface method of earth slope calculation, adopting the probability and mathematical statistics theory, this paper discusses the expressions for the expectation and variance of the stochastic variables in earth slope stability. 本文以常规圆弧滑动面法土坡稳定计算公式为基础,采用概率论和数理统计理论,探讨了影响土坡稳定性的各项随机应变量指标的期望和方差的表达式。