Abstract: Upon the infiltration of rain or flood, change of the stability of the river embankment is a very complicated process, that involves water movement in saturated-unsaturated states and the decrease in the strength of the unsaturated soil. Study of the water movement and the change of the soil mechanical properties would lead to the understanding of the dike collapse mechanism, thus would be helpful in reinforcing embankment and effective preventing flood damage. In this paper we analyzed and stated the dike collapse mechanism from two full-scale embankment infiltrating tests.