From the character of energy transformation on slope sliding curve, the stability analysis on double-and three-layer soil slope is calculated in order to take in energy dissipation method gaining an advantage over other calculated methods, including Bishop method and finite element method. Through the derivation of integral transform on slip line ,the safety factor formula is built based on modified limit equilibrium method to sliding curve, and the slip line formula is also obtained by limit safety factor value on differential coefficient of the slope safety factor equation. The slope examples on 2D strain are cited to validate the reliability on energy dissipation method. The WJED program for calculating safety factor and sliding line equation is firstly applied to evaluate stability for double-and three-layer soil slopes. The results show the parse formula for latent sliding curve accords with exponential equation for energy dissipation method and coincides with circle equation for Bishop method. Simultaneously, the safety factor for energy dissipation is one between two values obtained from Bishop method and finite difference method respectively. The experience on slope reinforcement engineering and its stability is obtained and the energy dissipation method is a supplement in the limit equilibrium method.