Aiming at investigating the environmental aging behavior of an organic composite coating (H53 coating) and the corresponding main environmental factors, three - years atmospheric exposure tests were carried out at six environmental test stations. After the atmospheric exposure tests, H53 coatings lost gloss and changed color in varying degrees, and a large area of corrosion appeared in Wanning. Based on the analysis of the evolution laws obtained from atmospheric exposure test and indoor accelerated test of H53 coating, it could be found that six months of atmospheric exposure was an important node for the discoloration of H53 coating. According to the correlation analysis between the main environmental factors and the aging data of H53 coating, the main environmental factor of gloss loss and discoloration of H53 coating in the early stage (0～6 months) was the sunshine, the main environmental factors of gloss loss in the middle and late stage (6～36 months) were temperature, precipitation and humidity, and the main environmental factors of discoloration in the middle and late stage were temperature, sunshine hours, precipitation and humidity. Besides, under - film corrosion of H53 coating occurred after atmospheric exposure tests, and the most significant under - film corrosion occurred in Wanning, which resulted in a large area of corrosion on the sample.
