Abstract: The seepage flow in dam foundation is mainly controlled by the intact degree and the sealing effect of its curtain. Its property is weakened by long-term physical and chemical actions of groundwater. In order to describe the process of the damage to the curtain, a multi-field coupling model for water-rock-seepage curtain of the dam foundation is made up of seepage model, solute transport model, geochemistry model and curtain erosion model, and all the models are calculated by FEM. The results show that the curtain efficiency decrease with the time. Calcium has been always in dissolution during the time stress period for simulation. The erosion extent at the bottom of the curtain is much quicker than that at its top part. And it’s the same for the upstream and downstream. Calcium dissolution is mainly induced by hydraulic condition and dispersion, and it varies in a non-linear way.