Abstract The generalized turbulent lubrication equation for isotropic rough surface bearings is presented by integrating the Hashimoto turbulent lubrication model and the Patir-Cheng laminar flow lubrication model. The finite difference method is used to solve the generalized turbulent lubrication equation and energy equation. And the variations for turbulent lubrication performance of journal bearing with the nominal eccentricity ratio and nominal average Reynolds number are obtained under the influence of surface roughness and journal misalignment. As the dimensionless surface roughness height of the bearing and the journal increases or the degree of misalignment increases, the dimensionless maximum film pressure, dimensionless load capacity and dimensionless misalignment moment of the bearing increases. The research of journal misalignment, thermal effect, and surface roughness is needed.