A new strength reduction finite element method is established based on the principle of strength reduction technology. We take the process of the strength parameters reduction as a brittle plastic stress drop course; and a strength reduction increment is set as convergence condition to determine whether the program out of circulation. The final reduction factor is the safety factor of slope stability. The theory can be easily extended to the three-dimensional slope stability analysis with high precision

and can find the sliding surface of the slope and its development tendency of failure. Through two case stidoes

the importance of the 3D slope model is shown; and it is suggested that when the geological condition is complex

we should carry out analysis from the three-dimensional angle rather than simply it to the two-dimensional problems.