The invention discloses a laser surface treatment method for improving the thermal corrosion resistance of a thermal barrier coating, belonging to the technical field of treatment of thermal barrier coatings. The method comprises the following steps: S1, ultrasonically cleaning the surface of the thermal barrier coating, and adjusting the spot shape of a laser to a rectangular shape; S2, adjustingthe laser in the step S1 to emit low energy density laser, and carrying out self-preheating scanning on the thermal barrier coating treated in the step S1; S3, adjusting the laser in the step S1 to emit high energy density laser, and carrying out re-melting scanning on the thermal barrier coating treated in the step S2; S4, adjusting the laser in the step S1 to emit medium energy density laser, and performing a slow-cooling scanning on the thermal barrier coating treated in the step S3; S5, naturally cooling the thermal barrier coating treated in the step S4 to room temperature, and then using compressed air to remove impurities on the surface of the coating cooled to room temperature. After the coating is treated by using the method, the coating is smooth and dense, the thermal corrosionof corrosive salt is inhibited, and the service life of the coating is prolonged.