During the running process of the highpressure gas well casing,it will suffer from uneven external load due to the bending deformation or vibration caused by the ocean load,and result in the nonuniform deformation of the joint seal structure and the decline of its sealing performance.The linear DruckerPrager plastic model was used to simulate the PTFE seal,which was used as the two stage seal of casing joint.Finite element model of highpressure gas well casing was established by ABAQUS,and the contact stress on the ring sealing surface under the action of internal and external pressure was analyzed.The results show that when the outer wall of the casing has concentrated load,the contact stress on the sealing surface is in wavy change.The contact stress on the sealing surface is the lowest in the 60° position on both sides of the concentrated load zone,and which is the area where the casing is easiest to leak.