Van Genuchten unsaturated seepage model is adopted for comprehensive saturated and unsaturated seepage analysis in this paper, and then an embankment dam is taken as an example to investigate the seepage and slope stability problems of embankment dams under rapid drawdown of water level. The results show that the fluctuation of the upstream water level has a great influence on the seepage flow of the dam under rapid drawdown of water level. The reverse seepage formed during the rapid drawdown of water level significantly reduce the slope stability of the embankment dams. However, the factor of safety for the upstream slope is increase to an extent when the dam pore water pressure is sufficiently dissipated.