In order to improve the structure and overall quality of the traditional laser cladding coating, the coating was prepared in vacuum environment. 304L + La2O3 coating was prepared on the surface of 45 steel. The macroscopic appearance, microstructure, phase composition, microhardness and friction and wear properties of the cladding layer were analyzed and studied. Results show that the vacuum environment can insulate oxygen and prevent oxidation in macroscopic appearance. The fluidity of the molten pool can be increased and the density of the microstructure can be improved. The hardness of cladding layer in vacuum is 797.9 HV, which is 13.4% higher than that in vacuum free environment. The friction coefficient and wear amount decreased 8.6% and 16.9%, respectively, and the wear resistance increased.