Abstract: The researches on the three-dimensional stability of rock slopes are of important theoretical significance and engineering application prospect. The conventional equivalent Mohr-Coulomb strength parameters used to analyze the stability of rock slopes cannot accurately reflect the nonlinear distribution of strength envelope of rock mass, resulting in conservative results. A point-by-point equivalent Mohr-Coulomb strength parameter is proposed to replace the conventional equivalent Mohr-Coulomb strength parameters. By constructing the normal stress distribution over the sliding surface, the equivalent cohesion and internal friction angle of the sliding surface change point-by-point with the normal stress distribution over the sliding surface. On this basis, a three-dimensional stability analysis method for rock slopes is proposed by combining the point-by-point equivalent Mohr-Coulomb strength parameter and the limit equilibrium method based on constructing the normal stress distribution over the sliding surface. Some examples show that the proposed method is correct and suitable for any spatial sliding surface shape. Compared with the conventional equivalent Mohr-Coulomb strength parameters, the stability coefficient obtained by the proposed method is lower. The method has successfully applied to a practical project and achieved good results. The results are reliable, and the calculation process is simple and easy to program, which can provide a theoretical reference for the stability evaluation of rock slope engineering.