Using Baotou steel blast furnace slag as the main raw material and a small amount of chromite, microcrystalline cast stone was prepared by one-step heat treatment method in the cooling process of high temperature slag liquid. Through melting point measurement, differential thermal analysis, X-ray diffraction, scanning electron microscope observation and physicochemical properties test, the influence law of chromite addition amount on crystallization behavior and physicochemical properties of microcrystalline cast stone ware studied. It opens up a new way for low cost and high value utilization of Baotou steel blast furnace slag. The results show that: when the raw material ratio is 95% of blast furnace slag and 5% (mass fraction) of chromite, the overall crystallization of microcrystalline cast stone, the main crystalline phase is magnesium and aluminum feldspar, the bending strength is 31.88 MPa, the density is 3.439 g·cm-3, the water absorption rate is 0.036%, the acid resistance is 0.145%, the alkali resistance is 0.033%, in line with the national standards for building materials. It can completely replace natural marble and granite as architectural decoration materials.