GB/T 23456-2009 specifies phosphorus plaster. It defines the concept of phosphorus plaster and clarifies its classification. The standard specifies the technical requirements of phosphorus plaster in terms of chemical composition and physical performance, such as calcium sulfate content, free water content, radioactivity specific activity and other key indicators. At the same time, it provides test methods for testing the performance of phosphorus plaster and inspection rules for determining whether the product is qualified. The standard provides a basis for the production, utilization and mass supervision of phosphorus plaster, which helps to promote the rational application of phosphorus plaster in building materials and other fields, promote comprehensive utilization of resources, and reduce environmental pollution.