Abstract: Fracture failure happened to a batch of H62 copper casings when assembling,and means such as chemical compositions analysis,macro analysis,optical microscopy and scanning electron microscopy observation were used to analyze the fracture reasons of the casings.The results show that the fracture of the H62 copper casings with the characteristics of intergranular mode was stress corrosion cracking which was induced by the combined action of assembling twisting force,internal residual stress and environmental factors.