Abstract: The flow structure and flame development were studied experimentally in a hydrogen-fueled scramjet combustor. Wall pressure measurement, schlieren, differential interferometry, high-speed framing of flame luminosity and OH-PLIF (planar laser-induced fluorescence) were introduced to characterize the combustion flow. The synchronous measurement path diagram of schlieren, differential interferometry and PLIF was developed in this study, and the coupling results of flow structure and flame were obtained. The results show that:in the five studied cases, the combustion flow structure is unstable when the equivalent ratio of hydrogen is greater than 0.17. The fragmentation flame spreads in the flow between the top and bottom wall. When the equivalent ratio of hydrogen is less than 0.17, the continuum flame is stable and located in the cavity shear layer.