To deal with the leakage problems of clamp connector,a calculation model was established and the formula of the pulling force of the cylinder was derived.The nonlinear finite element method was used to calculate the contact stress distribution disciplinarian and the base counterforce of O-ring between the base and the hub,to study the sealing performance and to improve the formula of the pulling force of the cylinder.By using finite element analysis to clamp connector,the von Mises regularities of distribution was obtained which indicated the frail parts of the clamp,and these frail parts had been improved.These works give some suggestions for design and intensity analysis of the clamp connections.