Numerical simulation is an effective way to study the temperature rise characteristics which directly affect the overheating of GIB (Gas-Insulated Busbar). In order to calculate the temperature of bus contact accurately, a conductive bridge model is introduced to simulate the current contraction effect and joule heat effect between conductor and contact fingers in the model formation stage. Direct and indirect coupling methods are combined to build the 3-D eddy current-fluid-thermal finite element calculation model. Temperatures of the GIB contact under different currents and ambient temperatures are separately calculated with the proposed model. Temperature rise tests on GIB prototype are carried out to verify the correctness of the numerical calculation model and the reasonableness of conductive bridge equivalent treatment.