The model of tooth and sliding combined seal was established to study the mechanical behavior and sealing performance of Oring and slip ring by the finite element method.The effects of compression amount,fluid pressure and tooth thickness of the slip ring on sealing performance were analyzed.The results show that the high stress area of Oring appears on the bottom of the groove,and the Mises stress of slip ring is mainly concentrated on the two sharp corners that the slip ring contacts with the groove and cylinder.The sealing performance is improved by increasing the compression amount,however the Mises stress is also increased.The sealing performance and the ability of the slip ring to resist deformation are increased with the increasing of tooth thickness of the slip ring.The improved scheme of chamfering was adopted to solve the problem of failure in the two sharp corners.After the chamfering,the maximum contact pressure of the main sealing surface is increased,but the Mises stress of the cross section is decreased under the same conditions.Therefore,the improved tooth and sliding ring has better sealing performance and longer service life.