Abstract: As an important structure in the flow field of jet in crossflow, the wake region has attracted wide attention. Its mixing and combustion characteristics have an important impact on the flow field near the wall. After the full verification of the simulation, the mixing and combustion characteristics of the high-enthalpy transverse jet in the wave region under Mach 8 flight conditions were numerically studied using Reynolds average Navier-Stokes simulation method. The mixing characteristics of hydrogen in the wake region of the cold and hot flow field were studied. The shock structure in the wake region of the cold flow field affects the distribution of hydrogen to some extent. There are several different hydrogen mixing paths in the wake region of the hot flow field. The flame structure in the wake region was measured quantitatively. The position of the flame vertex in the wake region moves downstream linearly with the increase of the height. Affected by the jet mainstream, the flame width begins to increase above a certain height from the wall. The main parameters in the cold and hot flow field were compared. The combustion consumes hydrogen to increase the temperature, but the flow velocity in the wake region does not increase significantly as the heat released by combustion does not completely convert into the kinetic energy of the fluid.