During the summer season (June-August) in Southern China and Southeast Asia, operational environments in most factories persist at high temperatures (30-35°C) and high relative humidity (>60% RH), despite running temperature and humidity control systems. Under these conditions, conventional electrostatic powders undergo significant performance degradation, causing typical defects such as low powder adhesion (powder fall-off, powder sliding) and high enamel thickness on the edge (fat-edge). Additionally, phenomena of “over-firing/boiling” are likely to occur during firing. To address these challenges, we developed an Electrostatic Enamel Powder Humidity Resistance Evaluation System. Utilizing this system, we succeeded in optimizing the powder’s humidity resistance performance and successfully developed an electrostatic powder product with excellent humidity resistance.