Abstract: The fracture of the valve body occurred after DN25 copper valve being installed in a heating pipe network for 2 months. The fracture causes of the copper valve were analyzed by means of macroscopic analysis, chemical composition analysis, fracture analysis, metallographic examination, hardness test and so on. The results show that the wall thickness of the copper valve was thin, and stress corrosion cracking occured under the combined action of chloried in the water and working stress, which eventually led to the fracture of the copper valve.