Abstract: Lead-bismuth fast reactor （LFR） and supercritical carbon dioxide （S-CO₂） cycle coupling system is a breakthrough technology to improve the efficiency of nuclear energy utilization and optimize the current situation of nuclear energy application.In order to accurately grasp the development and current situation of coupled heat transfer in this system,from the perspectives of intermediate heat exchanger technology development,printed circuit plate heat exchanger（PCHE） flow channel optimization,liquid lead bismuth alloy （LBE） and S-CO₂flow heat transfer mechanism research,LBE and S-CO₂coupled convection heat transfer mechanism research,etc.The relevant experimental research and numerical simulation results are summarized comprehensively.The results show that Z-type PCHE has moderate processing difficulty and excellent heat transfer performance,and adding straight or curved arc at the bend can greatly reduce the internal pressure drop of heat exchanger under the premise of slightly decreasing heat transfer rate.It is clear that this type of heat exchanger is the mainstream choice at present,and the structure optimization design idea of PCHE is given.The experimental study of liquid LBE flow heat transfer has the problem of narrow boundary conditions.Compared with the existing heat transfer prediction correlation formula,the corresponding heat transfer prediction correlation formula is given for different conditions such as rod bundle and round tube.The numerical simulation methods suitable for liquid LBE are compared and analyzed.The turbulence model and Prandtl number model using Reynolds time mean method are given.The principle and advantages of numerical simulation using four-equation model are explained.The research status and problems of S-CO₂heat transfer correlation,LBE and S-CO₂coupling heat transfer applied to PCHE are summarized systematically.At present,the research results of direct coupling heat transfer between LBE and S-CO₂are lacking,and there is still no mature conclusion to determine which heat exchanger structure is the most suitable,and which numerical model has the best reliability and the least deviation value,which still needs to be considered according to different application scenarios.The conclusion of this paper clarifies the application direction and difficulties of leadbismuth-supercritical carbon dioxide coupled heat transfer,and has important significance for the development of other similar new multi-fluid coupled heat transfer systems.