Abstract: When chrome-plating layer of chrome-plated parts is inspected by dye penetration, there are some problems such as cleaning of excess permeable fluid on the surface, spraying of imaging agent and difficulty in evaluating defect trace. Through the process practice research, the auxiliary tools of developing agent spraying were made, the process parameters of chrome-plating layer coloration and penetration inspection were determined, and the forms and properties of several main defect trace display were understood. At the same time, some problems that should be paid attention to in the process of chrome-plating layer dye penetration inspection are put forward, which provides reference for peers.