Chemical milling protective coating system materials are mainly composed of chemical milling protective coating,milling protective coating quick dry repair adhesive and milling protective coating line sealant.This paper mainly studied whether the paint film surface condition of multiple batches of engineering products of chemical milling protective coating system materials changed after chemical milling process,and whether the straightness of milling edges of machined parts and the size of etch ratio meet the requirements,for determining whether the chemical milling protective coating system material will affect the milling bath liquid after three batches of engineering products milling process verification.The results showed that the chemical milling protective coating system materials maintained good milling effect after batch milling,which had no affection on the milling bath fluid.