Focus on the urgent need to improve the wear resistance of Deloro40 nickel-based alloy, which is a valve material in the nuclear industry, this paper uses laser additive manufacturing technology to explore the effect of Mo on the microstructure and wear resistance of Deloro40 nickel-based alloy by adding different contents of Mo. Results show that the addition of Mo promotes the formation of Mo2C, Mo2O and Ni3Si2 phases. With the increase of Mo content, fine grain size and hard phase Mo2C formed in microstructure improve the hardness of the alloy. The wear rate of samples increased first and then decreased. MoO2 generated in the friction process played a lubrication role, which reduced the wear rate. It shows excellent wear resistance at 25 ℃ and 400 ℃ when 5% Mo was added.