Moulding powder spraying is the use of corona discharge phenomenon to make the powder coating adsorb on the workpiece. The process is as follows: the powder coating is fed into the spray gun by compressed air gas from the powder supply system, and the high voltage generated by the high voltage electrostatic generator is added at the front of the spray gun. Due to the corona discharge, a dense electric charge is produced near it, and when the powder is ejected from the muzzle, to form charged paint particles. Under the action of electrostatic force, it is absorbed to the workpiece opposite to its polarity, and with the increase of powder sprayed, the more charge accumulates. When it reaches a certain thickness, it will not continue to absorb because of electrostatic repulsion, so that the whole workpiece can get a certain thickness of powder coating, and then the powder will be melted, flattened and solidified by heating, that is, a hard coating film will be formed on the surface of the workpiece. No thinning, no pollution to the environment, no toxicity to the human body; excellent appearance quality of the coating, strong adhesion and mechanical strength; short curing time in spraying construction; corrosion and wear resistance of the coating is much higher, and the flow phenomenon common in the painting process will not occur in the process of electrostatic powder spraying.