A lubrication theoretical calculation model of thermal characteristic is proposed to study the temperature characteristics of a novel three-pad radial gas foil hydrodynamic bearing. The numerical simulation method is used to calculate the film temperature distribution of the gas foil bearing by coupling the non-isothermal Reynolds equation and the energy equation，and the effects of the rotor thermal expansion and the rotor centrifugal expansion on the bearing clearance are taken into account. The effects of the bearing load，speed and cooling gas flow on bearing temperature are analyzed. The results show that the peak temperature of the film is located at the downstream of peak pressure；the air film temperature increases with the rise of bearing load and rotor speed，and the results indicate that the rotational speed has a larger effect on the bearing temperature than the bearing load; the cooling effect of the airflow is obvious，and the bearing temperature decreases rapidly with the rise of the cooling airflow and then gradually calms down.