Taking the injection online pressure sealing of steel pipe welding neck flanges with raised face as the research object,the finite element models of its universal clamp and and new four equal clamp were established,and the mechanical properties were analyzed by using the finite element software ABAQUS.The results show that when the pressure is 6 MPa,the maximum circumferential tensile stress of the new four equal clamp is 6697% of that of the universal clamp,the maximum tensile stress of the bolt is 3816% of that of the universal clamp,and the deformation displacement is 9365% of that of the universal clamp.The new four equal clamp is superior to the universal clamp in both pressure bearing capacity and stress concentration.Therefore,it has higher bearing capacity and service life compared with the universal clamp.