By employing the Darcy’s law analytic expression expressed by hydrochemical indicators proposed by previous researchers for calculating hydrogeological parameters on theoretical basis of chemical thermodynamics, chemical kinetics, hydrogeochemistry, hydrogeology, and mineral dissolution kinetics, we calculated the permeability coefficient of seepage curtain in a compound dam foundation, and also the saturation index of calcite, dolomite, and gypsum in the water environment of dam site in full consideration of the impacts of complex compound in water. We analyzed the suitability and rationality of applying this method to seepage curtain by comparing the calculation results with in-situ permeability test results together with seepage control value, seepage amount, water pressure, and precipitation behind the curtain, and on this basis further evaluated the status of seepage curtain. Results demonstrate that permeability coefficient calculated by water quality indicators could well reflect the seepage status of grouting curtain. This paper is of referential value for evaluating the anti-seepage performance of grouting curtain in similar projects.