The lubrication performances of UHMWPE based polymer composite bearings were researched.A two-way fluidstructure interaction (CFD-FSI) method was used to study the influence of material parameters such as elastic modulus and Poisson，s ratio,as well as operating conditions such as rotational speed and load on maximum water film pressure,maximum bearing deformation,minimum water film thickness,and friction coefficient of waterlubricated journal bearings.The simulation method was verified by experiments using the modified UHMWPE composite bearing.The results show that the CFD-FSI method considering elastic deformation has higher accuracy in calculating polymer composite bearing performance.With the increase of elastic modulus and Poisson，s ratio,the load carrying capacity of bearing is increased and the deformation of bearing is decreased gradually.With the increase of load,the maximum film pressure and maximum deformation of the bearing are increased linearly,and with the increase of rotational speed,the maximum film pressure and the maximum deformation of the bearing are decreased significantly.For polymer composite bearings,the computational error that does not account for elastic deformation is larger under low speed and heavy load conditions