In this paper, through the laser cladding experiments of pure Co powder mixed with WC particles of different sizes and proportions under different technological equipment and parameters and cladding effect detection, it proved that the semiconductor laser with large fiber core diameter and large light spot is more suitable for metal based cemented carbide cladding. By reducing the energy concentration of the spot and reducing the input power to reduce the heat input, and increasing the WC particle size to reduce the thermal sensitivity of the WC particles, which can effectively inhibit the dissolution and decomposition of WC, and reduce the number and size of pores in the cladding layer. The cracking tendency of the cladding layer can be reduced by substrate preheating or full Ar protection. A large area of laser cladding WC-Co cemented carbide coating with a WC mass fraction of 60%, no cracking, and low porosity can be obtained under full Ar protection conditions, using input power 800 W, scanning speed 4 mm/s, powder feeding rate 11 Hz, or under substrate preheating 400-450 ℃ conditions, using input power 800 W, scanning speed 7 mm/s, powder feeding rate 11 Hz.