A method for preparing a ceramic package substrate with a copper-plated dam involves making a circuit layer on a ceramic base by performing thin film metallization, dry film application, exposure, development, copper plating, and evening, and then forming copper-plated dams that circle individual circuits by repeatedly applying dry film application, exposure, development, and electroplating for thickening, so as to obtain the ceramic package substrate with the copper-plated dam. Circuits made using the method feature for high dimensional precision, high line resolution, and high surface evenness.