Abstract: The foundation of an arch dam often contains soft seams or consists of rock strata with diffrient properties. Therefore photoelastic stress analyses of an arch dam on non-homogeneous foundation are improtant and complicated. In this paper the stress analysis of a high arch dam together with its complex foundation by using photoelastic study of a three-dimensional model is presented. Some problems are described briefly such as casting combined model and loading analogy on it. The performance of the dam and the stress distribution in the dam under hydrostatic water load and silt pressure have been analyzed. Besides, the effects of variation in elastic modulus of foundation, asymmetry of the elastic moduli and existence of low modulus zones in the foundation on the stress in the dam are also disrcussed.