In order to investigate the influence of seat structure and sealing pair material on the sealing performance of the deep water test blowout preventer valve,the mechanical model was established by considering the influence of O-ring and hydrostatic pressure on sealing force,and the sealing mechanics characteristics in testing operation were analyzed.The finite element model of the sealing structure was established,and the influence of the position of sealing groove,the width of sealing surface,the elastic modulus of the sealing seat material and the friction coefficient on the contact pressure and Mises stress of the sealing surface was analyzed.The correctness of the analytical model was verified by theoretical formulas.The results show that the contact pressure and Mises stress near the sealing surface diameter are increased with the decrease of the distance between the sealing groove and the sealing surface,the contact pressure and Mises stress are decreased with the increase of the width of sealing face.The elastic modulus of sealing seat material has little effect on the contact pressure and Mises stress.The increase of friction coefficient will cause the increase of Mises stress and the decrease of contact pressure,while the friction coefficient exceeds 0.8,it has little effect on the contact pressure and Mises stress.The following conclusions can be drawn that the position of sealing groove,the width of sealing surface and friction coefficient can locally adjust the distribution of contact pressure and Mises stress on sealing surface