Thermal characteristics of a spiral grooved journal bearing under steady and concentric operating state are investigated in this paper by applying Thermo-Hydrodynamic Lubrication (THL) analysis with introducing a model consisting of a shaft, bearing sleeve and oil film in the bearing clearance. The analytical solutions for temperature distribution in the bearing clearance are compared with experimental results, thus confirming the validity of the theoretical model. Detailed parametric studies with changing Peclet number, circumferential bearing number, clearance ratio, heat transfer coefficient and sleeve thickness show that the representative values of dimensionless temperature raise of the bearing are directly proportional to Peclet number, and inversely proportional to clearance ratio squared or powered by somewhat a less magnitude, and heat transfer coefficient.