The invention discloses a method for preparing a modified composite Hf-Ta metal coating through laser cladding. The method comprises the steps that firstly, refractory metal is subjected to acid pickling after polishing treatment and then subjected to sand blasting treatment and ungrease treatment in sequence; secondly, mixed powder and a dispersing agent are placed in a ball mill to be subjected to ball milling and mixed evenly to obtain modified composite Hf-Ta slurry; thirdly, the modified composite Hf-Ta slurry is pre-placed on the surface of the refractory metal to obtain a pre-placed layer on the surface of the refractory metal after drying, then presintering treatment is conducted, and a presintered layer is obtained on the surface of the refractory metal; and fourthly, laser cladding is conducted on the presintered layer, and the modified composite Hf-Ta metal coating with the thickness being 30 [mu]m-800 [mu]m is obtained on the surface of the refractory metal. According to the modified composite Hf-Ta metal coating prepared through the method, the oxidation resistance of the refractory metal in a superhigh-temperature and low-oxygen-pressure environment can be significantly improved, and short-term protection can be provided for the refractory metal in a superhigh-temperature oxidation environment or an ablation environment.