Abstract: Based on the strength reduction theory, the factor of safety K of high slope structure is calculated using finite element method (FEM) (software -MIDAS/GTS). The sliding strip of slope structure is found at first. The input data and the output data used in the FEM are disposed again. Then the relation f1 (and f3) between basic random variables c,f and 1 (and 3), which are most (and least) main stress, may be found. So, the high slope structural function Z can be changed into explicit form from the original implicit form using above relation f1 and f3. Based on this explicit function Z, the reliability index 1 of each failure element within a sliding strip is computed using Monte Carlo method. The area Ai of above element is taken as weight coefficient. Then the slope structural whole reliability index  can be given based on the mean value, which is the result of all the failure elements i multiplied by Ai . The result of example shows that the present method is reasonable and feasible. It may simplify the computation program of slope structural whole reliability. And it can also be taken as a theory reference in high slope structural stability analysis.