The effect of vacuum test condition on the microstructure and properties of the laser cladding Ni-based WC coating is investigated. The results denote that under vacuum test condition, the microstructure of the coating is improved, the coarse dendrites in the coating are reduced, and the structure becomes denser and more uniform. The microcracks in the coating are significantly reduced, and there are almost no porosity defects. The intermetallic compounds in the coating are uniformly dispersed in the Ni-based solid solution, which significantly increases the hardness of the coating. In addition, the friction and wear properties of the coating are significantly improved. The friction coefficient is reduced by approximately 14% when compared with that in the non-vacuum condition, whereas the wear resistance is increased by approximately 56%. Under vacuum test condition, the overall performance of the coating is significantly improved.