The chemical composition, methylene blue value, and mineral composition of sandstone in the Jingmen area Hubei province were analyzed. The sandstone is used as admixture to produce composite Portland cement. The effect of different type and ratio sandstone on cement consistency, setting time and strength were studied. The feasibility of sandstone as admixture in composite Portland cement is verified. The results show that the type and ratio of sandstone should be strictly selected and controlled in composite Portland cement, and the appropriate dosage of sandstone is 3%~4%,otherwise cement will be difficult to meet the requirements of engineering construction.