Numerical analyses on a mixing of an injectant and a supersonic crossflow were performed. The modified mixing analogy was numerically validated by comparing the deduced mass fraction with the mass fraction directly solved from multi-species calculations. The simulation results reveal that the original mixing analogy underestimated the injectant mass fraction because of disagreement between heat transfer and mass transfer. The modified mixing analogy was able to evaluate the injectant mass fraction more adequately than the original mixing analogy. The injectant mass fraction slightly depended on the injectant total temperature because an increase of the injectant total temperature reduced the injectant mass flow. The total temperature distribution appeared in the simulated flow field, and the enthalpy deficit factor in the modified mixing analogy represented the total temperature distribution. This implied that the enthalpy deficit factor played an important role in the modified mixing analogy. The modification of the mixing analogy is required when the analogy is applied to the compressible flow.