Turbulent structure and mixing state of hydrogen and ethylene jets transversely injected into Mach 1.9 supersonic crossflow was numerically investigated using large-eddy simulation. The feature of windward large-scale structure was largely different between the hydrogen and ethylene jets. The ethylene jet had a highly intermittent feature with intensive geometric change of jet plume. The hydrogen jet had much larger velocity difference between the jet and the crossflow in the near-field, thus much higher turbulent intensity was obtained than in the ethylene jet. In addition, the scale of energetic eddy of hydrogen jet was larger in the windward mixing layer. These probably result in the better mixing in the hydrogen jet than in the ethylene jet.