The invention provides a resin light filter and a preparation method thereof. The resin light filter comprises a substrate, wherein a modified dispersion resin layer is arranged on the substrate, andthe modified dispersion resin layer is internally mixed with an infrared absorbing agent; the infrared absorbing agent is evenly distributed in the modified dispersion resin layer, and the modified dispersion resin layer is capable of filtering out infrared light; the modified dispersion resin layer is coated with a repair coating layer. The preparation method of the resin light filter comprises the following steps: S1: preparation of the modified dispersion resin, S2: preparation of the infrared absorbing agent; S3: mixing mixed solvents in S1 and S2 with each other and stirring. The resin light filter has the advantages that 1, the light filter uses a modified easily dispersible resin to ensure that the added infrared absorbing agent particles are evenly dispersed in a resin material, and the particle size is in nanometer scale, which does not affect the light transmittance; 2, the dispersing property of the specially configured infrared ray absorbing agent is strong, thereby ensuring uniformity; 3, the specially arranged repair coating layer can greatly improve the wear resistance of the surface of the light filter.