Abstract: In view of the urgent need of scramjet combustion diagnosis, especially the visualization of flame space structure, it needs to realize three–dimensional measurement of the supersonic flames. The Three Dimensional Laser–Induced Fluorescence （3DLIF） technology can realize the visualization of the flame combustion space. For the supersonic coaxial jet combustion, a scanning galvanometer multi–plane 3DLIF experimental device was built, and a laser sheet shaping scheme with expanded scanning range was proposed, which realizes the multi–plane 3DLIF visualization of the supersonic flames. The interpolation algorithm was used to reconstruct the three–dimensional average image of supersonic flame with a spatial scale of 50 mm×85 mm×20 mm and a time scale of 5 ms, which verifies the feasibility of using the 3DLIF technology to visualize the combustion space structure of the scramjet test bench. The effect of the flame speed on the flame structure shape using the three–dimensional images is discussed.