Abstract: Taking the Yizhuang tailings dam as project background，through indoor screening test and penetration test of the scene deposition Beach surface and drilled sampling，the deposition law of particle are obtained.A generalization of geological model is established；and through three triaxial test on the general model of different strata tailings obtained its stress-strain relationship，the saturated water content,basis on the residual moisture content,aturated permeability coefficient and the tailings grading curve，using Fredlund-Xing model to obtain the soil-water characteristic curve and flow models，With the theory of effective stress，establish the upstream tailings reservoir fluid-solid coupling mathematical model，By analysed the stress field and the seepage field of the tailings dam，the distribution of stress field and pore pressure are obtained，The research results can provide instructor for the design，construction and safe production of tailings dam.

Key words: Tailings dam, Upstream, Fluid-solid coupled, Unsaturated seepage