In the reliability analysis of slope,the performance functions derived from the most available stability analysis procedures of slopes are usually implicit and cannot be solved by first-order second-moment approach.A new reliability analysis approach was presented based on three-dimensional Morgenstern-Price method to investigate three-dimensional effect of landslide in stability analyses.To obtain the reliability index,Support Vector Machine (SVM) was applied to approximate the performance function.The time-consuming of this approach is only 0.028％ of that using Monte-Carlo method at the same computation accuracy.Also,the influence of time effect of shearing strength parameters of slope soils on the long-term reliability of three-dimensional slopes was investigated by this new approach.It is found that the reliability index of the slope would decrease by 52.54％ and the failure probability would increase from 0.000 705％ to 1.966％.In the end,the impact of variation coefficients ofc andfon reliability index of slopes was taken into discussion and the changing trend was observed.