Abstract: The present invention provides a method for trimming molds of automotive metal sheets, which comprise a top mold and a bottom mold. The top mold has a concave mold surface, and the bottom mold has a corresponding convex mold surface. The method comprises: 1. Use the top mold as the base mold, and smear dye on the top mold; 2. Close the bottom mold to the top mold; and 3. Polish the mold surface of the bottom mold. Thereby, the processing method according to the prior art is broken through, and an ergonomic trimming operation is hence provided. Accordingly, the trimming process is simplified, and the labor hours are reduced. Beside, the accuracy of trimmed molds is improved and the subsequent mold-clamping process can be omitted. Thereby, the exterior quality of the metal sheets can be enhanced while reducing substantial labor hours, and economic benefits for manufacturing molds of metal sheets for an automotive body can be achieved.