The test uses a ternary cementing system of ordinary Portland cement, sulphoaluminate cement and hemihydrate gypsum, and chooses machine-made sand as fine aggregate to prepare fully machine-made sand cement-based self-leveling mortar; chooses fly ash, stone powder and silica Ash as a mineral admixture to study the influence of mineral admixtures on the fluidity, compressive and flexural strength and dimensional change rate of cement-based self-leveling mortar made of fully machine-made sand. The pozzolanic effect of mineral admixtures has a positive impact on the development of the mechanical properties of self-leveling mortar, and the fluidity of self-leveling mortar decreases with the increase of silica fume content. The formula of self-leveling mortar is optimized through orthogonal experiments, and the best content of the excellent mineral admixture:fly ash 7%, limestone powder 4%, silica fume 1.0%.