In response to the repair requirements of U75V rails, a laser wire-filled cladding process test was carried out, and the cladding layer formed under the optimized process parameters was tempered and heat treated. By comparing the properties of the base material and the rail welding repair requirements, the effect of tempering on the microstructure and properties of the cladding layer was investigated. Results show that after tempering at 300 ℃, the heat-affected zone is mainly tempered martensite, the hardness does not change significantly, and the hardness gradually increases near the fusion line in the cladding zone. After tempering at 600 ℃, the overall wear resistance of the cladding layer is weaker than that of the steel rail, and the difference between the average hardness of the cladding zone and the heat-affected zone and the base metal is less than 15%. The heat-affected zone is mainly tempered sorbite, and its wear amount and friction coefficient in the wear resistance test are smaller than the rest of the cladding layer. The tensile strength and elongation of the cladding area after tempering at 600 ℃ are basically the same as those of the base material, which meets the corresponding performance requirements for rail repair.