Abstract: PTFE/PI combined insulated aerospace wires are extensively used in aerospace vehicles, and current carrying capacity is an important factor for the design of electrical wiring interconnection system(EWIS). Based on multi-physics coupled model, three specifications of wires, 6 AWG, 10 AWG and 16 AWG, were chosen to simulate current carrying capacity by COMSOL. Besides, simulation results were compared with measured data and the data from SAE AS50881H:2023, to verify the correctness of simulation. The study could provide a reference for the design of aviation EWIS without numbers of experiments.