Genetic algorithm is used in three-dimensional slope stability analysis. The slip surface of 3D slope is complicated
so it needed to be simplified. The slip surface is assumed to be formed as ellipsoid by seven parameters; and then the most possible slip surface which has the lowest safety factor will be searched out through genetic algorithm. If the slope has the explicit slip surface
the slip surface will be regarded as the whole slip surface; and the whole safety factor will be calculated. And then the local slip surface which has the lowest safety factor will be searched by genetic algorithm.