GB/T 20312-2006 specifies the determination method of moisture absorption performance of building materials and products. The standard specifies the test environment, such as environment box parameters under different Humidity conditions. Detailed description of the operation process of preparing the specimen and placing it in a specific Humidity environment. Moisture absorption and moisture absorption rate are calculated by measuring the mass change of the specimen after absorbing moisture within a certain period of time, so as to evaluate the moisture absorption performance of the material. The standard provides a key reference for the application of building materials in humid environments, and helps to screen materials with suitable moisture absorption performance. It is of great significance for the improvement of building moisture resistance, heat insulation and other performance and indoor environment regulation, and ensures the long-term use of the building Stability.