A complete coupling analysis interface software named INTESIM-ETFMotor was developed by INTESIM (Dalian) Co. Ltd. to realize the electromagneticthermal-fluid coupling analysis of automotive permanent magnet synchronous motor. The comparison of the results between the electromagnetic-thermalfluid coupling method and the traditional simplified decoupling method shows that  a simplified decoupling model cannot guarantee the temperature continuity and energy conservation, which does not reach the true thermal equilibrium. Thus, it is necessary to conduct the bidirectional coupling analysis.