Abstract: The SMR system for classification of slope rock masses is briefly introduced and applied in two representative wedge sliding red rock slopes to the stability of macroscopical evaluation. In the course of evaluation,great importance should be attached to predominant structural planes that dominate the slope failure, and these predominant structural planes shoud be taken as dominating component in structural plane evaluctin in the SMR system, which would lead to a good SMR consistent with the fact of slope failure. The effect of in-situ stress is analysed qualitatively, and the result indicates that the SMR system should be applied very carefully in high in-situ stress area.