In order to study the influence of initial installation deformation of floating oil seal O-ring,based on the Ansys Workbench platform,a two-dimensional axisymmetric finite element model of the floating oil seal was established,and the nonlinear contact analysis during the installation process was carried out by considering initial installation deformation of floating oil seal O-ring.The effects of different oil pressure,installation clearance,and hardness on the stress,contact pressure,contact friction force of the O-ring and the supporting reaction force of the floating seal ring end cover were studied.The results show that when considering the installation process,the O-ring is not located in the relatively central position in the floating oil seal,but in the upper position in the middle of the floating oil seal,and the maximum von Mises stress of the O-ring is greater than that without considering the installation process,so considering the installation process of the O-ring is more in line with the actual situation.The maximum von Mises area will become smaller and narrower with the increase of oil pressure,which will increase the risk of crack failure.The maximum contact friction is concentrated on the end face of the floating seal ring,and the contact length increases continuously with the increase of oil pressure.The increase rate of the force in the y direction of the floating seal ring end cover far exceeds the increase rate of the force in the x direction.Under the condition of constant oil pressure,the stress increases with the decrease of installation clearance,and the stress increases with the increase of hardness.The maximum contact pressure of the floating oil seal is greater than the oil pressure within the oil pressure range of 2 MPa,which can ensure the self-sealing of the floating oil seal.