Abstract: Parameter inversion is an effective way to obtain more reliable strength parameters of slope. In the article, after discriminating the position of the critical slip surface, the explicit formulas for inversion of strength parameters are deduced by the established relation between strength parameters and one to one relationship among strength parameters, and the critical slip surface. The classical Swedish slice method is used for calculating the factor of safety. Then, the inversion results are used to study the stability of slope reinforced by anchorage cable. Through analyzing actual case, the feasibility and practicability of the current method are verified. Some conclusion are obtained as follows:(1)Pre-stress cable has an effective reinforcement on slope. Its role on slope stability is more effective when the position of pre-stress cable on slope surface is more near to the lower sliding point of the slip surface; (2)The calculated factor of safety is larger as the pre-stress of cable is larger. Increase of horizontal inclination of anchorage cable has small effect on the calculated factor of safety.