Abstract: After the three gorge large dames of the Changjiang River reservoir water, the water level will reach 175meters, and surface average wave height will reach 1meter high. Therefore the wave action cannot be neglected for the stability of the rock slope. Based on the mechanical analysis of the rock mass slopes with a belt of weak intercalated layer acting on the wave, this paper obtains that the accumulation of deformation which causes layers weakening and time are the main factors lead to the rock mass slope fault, and finally the stability Evaluation equation considering time factor of wave action is established.