Abstract: The distribution of the Stress in casing connection, the value of make-up torque and thread off load are studied when the casing connection is assembled or loaded with internal pressure and axial tension, which are very important for gluing, leakage and thread off failure analysis. The comprehensive experimental research on casing connection is completed by advanced full-scale experimental at present, and the experimental result is analyzed. The cognitive level is raised by results of experiment and analysis for mechanical properties of casing connection. and the useful data are provided for the further research in theory.