The problems of local bubbles encountered during the construction of water-based coatings were analyzed and researched,and with the principle of bubble generation,the problems were investigated.The results showed that the directly reason for the defect were the thickness of the paint film and the heating rate of the flash drying furnace,and the root cause was the poor defoaming ability of the paint itself,and relevant solutions were put forward for the bubbles,which had important guiding significance for effectively controlling the quality of car body paint.