With the rapid development of the modern equipment manufacturing industry, resource consumption and economic losses caused by material wear are becoming increasingly significant. The research and progress of the wear-resistant cast steel not only helps to improve production efficiency, reduce resource waste and reduce economic losses, but also plays a positive role in promoting scientific and technological progress and the development of equipment manufacturing industry. In this paper, Mg is added to 35Cr2Ni2Mo cast steel, which provides the research basis for the popularization and application of new high performance wear resistant cast steel. The microstructure of the steel was observed by optical microscope, scanning electron microscope and transmission electron microscope. The hardness and mechanical properties of the steel were measured by a microhardness tester and tensile testing machine, and the wear resistance of steel was measured by friction and wear testing machine. The results show that after the addition of Mg, the microstructure of the cast steel remains lath tempered sorbite, with a finer carbide size. The proportion of non-metallic inclusions with small size is greater. The strength and hardness increase, the toughness decreases, and the wear resistance is better.