Abstract: In this study, the passive residual heat removal heat exchanger of AP1000 was used as the prototype. A heat transfer experiment of passive residual heat removal heat exchanger with three C-type tubes was carried out. And then subcooled test conditions were numerically simulated by CFD software. Through numerical calculation, the correlations for calculating the heat transfer of the outside of the tube were obtained. The calculated results using the adopted heat transfer model were in good agreement with the experimental data. With the heat transfer model, the design condition of AP1000 was also verified. It shows that the heat exchanger of AP1000 can remove the core residual heat. Therefore, the model is properly conservative and it can provide a technical support for design and safety analysis of large advanced pressurized water reactor.