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