Abstract: Making up and breaking out tests, thermal cycle gas-tight tests, internal pressure and tension tests under bending condition, tension to failure tests, and internal pressure to failure tests were carried out to ϕ139.7 mm×7.72 mm J55 low pressure gas-tight casing joint samples. The results show that the anti-gluing property of the joints was good, the sealing capability was qualified both under the condition of the temperature of 135℃ and the pressure of 35 MPa and under the condition of the pressure of 30 MPa, the bending dogleg angle of 10°/(30 m) and the tension load of 80% nominal yield strength. The leakage failure internal pressure and the tension strength of the joints were all much higher than those of the standard technical requirements.