This standard specifies in detail the test method of durability of coatings under heat and humidity conditions. The test uses a Conditioning box with a standardized sample size of 70x150x0.8-2mm and equipped with a heater for testing. The sample needs to be prepared using the same process as the actual product under inspection, and the influence of substrate material and pretreatment is taken into account. The test includes edge sealing treatment, sample preparation, exposure to the Conditioning box after pretreatment. The test period is 21 days, and the surface changes are checked at intervals, and the durability and change of the coating are specially recorded. The standard emphasizes the importance of sample inspection and condition setting before the test to ensure the Stability and Reliability of the coating in the heat and humidity environment. This guide highlights standard test methods, important steps, and objectives to help understand and apply to coating durability assessment and product quality control.