The invention relates to a nitride passivation method for cavity surfaces of a vacuum-cleaved high-power semiconductor laser, belonging to the technical field of a semiconductor optoelectronic device process. The purpose of the method is to increase an optical catastrophe threshold, reduce the degradation rate of the laser, and prolong the service life of the laser under the condition that the output power of the semiconductor laser is not changed. The method comprises the following steps: first, a semiconductor laser chip is cleaved into bars in a vacuum-cleaving machine, high-purity nitrogen is filled in the process as a protective gas, the whole cleaving process is in the atmosphere of high-purity nitrogen, and fresh cavity surface dangling bonds are decreased after cleavage. After cleavage, the laser chip bars are rapidly put in a vacuum coating machine, nitrogen ions are used for carrying out cavity surface depth passivation to form a GaN passivating layer, and useless impuritiesgenerated by nitride passivation are removed through hydrogen ions. After the semiconductor laser forms the GaN passivating layer, a front cavity surface and a rear cavity surface are respectively subjected to anti-reflection film and high-reflection film plating. The technical scheme can be applied to the manufacturing of various high-power semiconductor lasers.