According to the rock engineering property and stability of high-steep open-pitslopes, various factors were collected on the basis of rock engineering system (RSE) theory,and the interaction matrix of stability evaluation was established.Then, the stabilityevaluation index (S_p) of the slope was put forward.Ranges of the S_p value and the correspondingstable state were given on the basis of thirty-six samples.It is found that the followingrelationships exist: unstable (easy landslide): S_p<-0.20; mid-stable (may be landslide):-0.200.63.Finally, the stability evaluation indexwas applied on the high-steep open-pit slope of one mine.Analysis results and monitoringdata indicate that the index meets the necessity of the property of slope engineering, and ithas an important engineering purpose for landslide forecasting of high-steep slopes. According to the rock engineering property and stability of high-steep open-pitslopes, various factors were collected on the basis of rock engineering system (RSE) theory, and the interaction matrix of stability evaluation was established. Shen, the stability evaluation index (S_p) of the slope was put forward. Ranges of the S_p value and the correspondingstable state were given on the basis of thirty-six samples. It is found that the following relationship exist: unstable (easy landslide): S_p <-0.20; mid-stable ( may be landslide: - 0.20 0.63.Finally, the stability evaluation index was applied on the high-steep open-pit slope of one mine. Analysis results and monitoring data of that index meets the necessity of the property of slope engineering, and ithas an important engineering purpose for landslide forecasting of high-steep slopes.