Thin film pretreatment is a green and environment-friendly pretreatment process that replaces phosphating in the coating pretreatment process.Compared with traditional phosphating,the film is finer and thinner,and its anti-corrosion performance has not been verified by the market for a long time in China.In this paper,a preliminary exploration of the pre-treatment technology of the needle film is carried out,including the research on the product performance after electrophoresis and the research on the design of the thread body,equipment requirements and thread body process maintenance.