Defoamers divided by press ingredients: natural oils (i.e. soybean oil, corn oil, etc.), polyether-based defoaming agent, higher alcohol, silicone, polyether-modified silicone. Following functional alkali defoamers, defoamer acid, a highly viscous foam defoaming agent. And an antifoaming agent mainly used in the aqueous coating are: (1) metal soaps, waxes, mineral oil system with floating the transparency is poor in compatibility, mainly for industrial primer system of high PVC.