In the thermal spraying of nano-WC-Co composite powder, it is suitable to use high-speed oxygen flame spraying. Compared with other spraying methods (such as low-speed combustion spraying method, ordinary plasma spraying method, high-energy plasma spraying method, etc.), the flame is compared. The temperature is relatively low, the particle speed is relatively fast, and the decomposition rate of wc in the oxidizing environment of flame or plasma is minimized, the retention of wc in the coating is high, and the wear rate of the coating is low. In order to prevent oxidative decarburization of the nano-WC-Co cemented carbide powder during thermal spraying in the surrounding air environment, the spraying should be carried out in a vacuum.