<p>Temperature distribution is an important factor affecting the flow field inside the rotor of a gas centrifuge, as well as the separation performance of the latter. A numerical iterative calculation method of the whole temperature field of gas centrifuge can be established by deducing the numerical theory of radiation heat transfer between the centrifuge rotor and the sleeve, and by using the continuous condition at the fluid–solid boundary. Using the numerical method, one can obtain more accurate results of the temperature field and flow field, as well as calculate the separation power of the gas centrifuge. The effects of the key heat transfer parameters on separation performance and temperature field of subcritical gas centrifuge, such as blackening treatment at the inner surface of the sleeve, length of the reflector, temperature of the cooling water, and the position of the water jacket, were studied using this numerical method, based on the Iguassu centrifuge model. The calculation results can provide several references for the design and optimization of the heat transfer of the gas centrifuge.</p>