The invention discloses a method for preparing a light-resistant paint, and belongs to the technical field of paint preparation. The method comprises the following steps: mixing rosin, safflower oil, petroleum, and deionized water with the electrical conductivity less than 5 [mu]S/cm, and heating to 105-110 DEG C for 1 to 3 hours; then under the ultrasonic condition that the ultrasonic power is 80W and the ultrasonic frequency is 50 Khz, adding epoxy resin, cardanol, zirconium oxide, sulfur and pigment, and conducting ultrasonography for 30 to 60 minutes, meanwhile irradiating with ultraviolet rays, and finally grinding the prepared material to be the particle size less than or equal to 10 nanometers. According to the method, primarily, the rosin, the safflower oil, the petroleum, and the deionized water with the electrical conductivity less than 5 [mu]S/cm are mixed and subjected to heating reaction, then epoxy resin, cardanol, zirconium oxide, sulfur and pigment are subjected to ultrasonography under the specific ultrasonic condition, meanwhile the ultraviolet rays are used for irradiation, and finally the prepared material is ground to be the particle size less than or equal to 10 nanometers, so that the light resistance of the product is improved.