The present invention provides a modified repair solution, a preparation method thereof, and a method for repairing color resist. Through adding additives to a photoresist solvent, a ketone compound in the modified repair solution is adsorbed on a surface of a source/drain metal layer to chemically react with a molecular linker to form a transparent colloid. The colloid is colorless and transparent, insoluble in water and organic solvent, and has strong adsorption with aluminum. After the transparent colloid is formed, further formation of the colloid is prevented, and aluminum is prevented from contacting with alkaline modified repair chemical solution, thereby preventing aluminum from being corroded; moreover, the chemical solution can be prevented from remaining in a damaged portion of a protective layer, and reaction with aluminum at high temperatures in post processing can be prevented, thereby preventing a vertical disconnection.