This device is a major technological innovations by our company, and a revolutionary new process for surface treatment of cold-rolled steel door panel products. Applicable to thickness range of 0.3-2.5mm of cold-rolled steel door panel, with design of complete program control to achieve a fast processing of degreasing, roughening, inactivating, and drying off cold-rolled steel plate, and which occupies less room than traditional phosphating process devices. The adhesion of coated layer has been greatly enforced which is suitable for the successive mechanized re-processing, stabilizing the surface treatment quality, lowering operation costs, and pollutant emissions qualified. Either a steel coil can be processed continuously or a single door panel can be processed one by one.