In this paper the influence of gypsum-water ratio, filler types and calcination temperature on gypsum bending strength were analyzed by the means of experiments. Spiral-shaped gypsum mold was made by gypsum molding material and mobility experiment was conducted on Pb-Sn alloys. Compared with pure gypsum, gypsum mixture had better mechanical properties. The fluidity of the alloy in the gypsum mold was prone to casting pressure, pouring temperature and alloy ratio. The research results have benefit to the development of gypsum casting technology.