The external-combustion wave rotor utilizes the unsteady pressure wave formed by the opening and closing of the ports to perform high-efficiency energy conversion, which has a wide range of application prospects. The typical structures of internal flow field of the external combustion wave rotor are analyzed, the global important results of performance tests are reviewed, and the advantages and challenges of topped gas turbine are summarized.It is pointed out that under the influence of port gradual opening and closing, circumferential clearance leakage, centrifugal force and Coriolis force acceleration, and solid wall heat transfer, the internal flow field structure presents multi-dimensional characteristics, and the leakage loss accounts for the largest proportion.Under model test condition, a pressure gain of 15～30% and a compression efficiency of 70～85% can be obtainedWhen used in conjunction with a gas turbine, it has the advantages of through-flow self-cooling, outstanding steady-state performance, excellent dynamic response and insignificant size effect. However, it is necessary to overcome the bottlenecks such as compact overall stricture design, high performance wave rotor design, wide operating condition wave system structure control, low-loss transition duct design and compound loss suppression.