Abstract: The corrosion causes of chromium plating on the inner wall of different parts of tubular parts were analyzed. By improving the processing technology, the corrosion caused by the collapse of chromium coating around the screw hole was avoided; and the large area corrosion caused by the water accumulation at the tail end was solved by improving the design of the nozzle cap. By controlling the thickness of chromium plating layer, sealing treatment after plating and daily maintenance, the corrosion of chromium plating layer in other parts was improved. It is significance for improving the service life of products.