Based on the theory of ultimate equilibrium, an improved General Limit Equilibrium method (IGLE) is studied, and it is implemented in Rslope software. IGLE can simulate various limit equilibrium methods and takes into account external factors(water、tensile crack、external load) and reinforcing measures(anchor、anchor-cable、geotextile、soil nail). Imbalance thrust force method is simulated in this study, and analysis on precisions of safety coefficient and residual pushing force under two conditions of imbalance thrust force which are strength reserve method and overload method respectively by using IGLE is conducted. The study also promotes an effective usage recommendation. Aiming at the problem that engineer is easy to confuse residual pushing force with inter-slice force, comparative analysis on horizontal components of inter-slice force and residual pushing force is conducted. The results show that there is no direct correlation between them. Then the results of calculation examples of Rslope are compared with other commercial soft wares, such as slide, SLOPE/W. Specifically，the comparison includes automatically searched safety factor of circular slip surface, safety factor of sliding surface and safety factor of reinforcement. The results have a good consistency. IGLE is of practical significance for real applications.