To calculate the temperature field of bump foil gas bearing, and to analyze its thermal characteristics, considering outer cooling condition and specific foil structure, the equivalent heat convective coefficient on the inner side of top foil is derived, and the heat conductive and convective models of bearing sleeve and rotor are established respectively. Non-isothermal Reynolds equation, energy transfer equation of gas film and foil deflection equation are solved. The influences of bearing load, out cooling condition, bearing speed, etc. on bearing temperature are finally obtained, and the static and dynamic performance of the bearing is calculated. The results indicate that the bearing temperature is very sensitive to the bearing speed, and the cooling efficiency of the out cooling flow becomes weak with the increase of the cooling mass flow rate. The smaller nominal clearance plays a more important role in influencing the bearing temperature than the larger one. In addition, with the temperature effects considered, the bearing will achieve higher load capacity, larger dynamic stiffness and damping coefficients.