Abstract: The junction temperature calculation of insulated gate bipolar transistor(IGBT) is of great significance for evaluating its remaining life and ensuring the reliable operation of power electronic converters. The traditional thermal network method ignores the real heat transfer process between the module and the radiator, and it is difficult to calculate the junction temperature change accurately and effectively. To address this, a calculation method of IGBT junction temperature with thermal network model considering flow-thermal coupling is proposed. In this method, the thermal network model of IGBT module and the radiator is extracted by the finite element simulation considering the flow-thermal coupling, and the junction temperature of the IGBT is calculated based on the easily obtained radiator water temperature as the temperature reference point. In order to verify the validity of the model, a power cycle accelerated aging test platform is built to extract the junction temperature change curve. The results show that the proposed thermal network model can calculate the IGBT junction temperature more realistically and accurately. And it can provide more real and accurate junction temperature change data for the reliability evaluation and remaining life prediction of IGBT modules in practical applications.