Abstract: The development of the supersonic mixing layer is an important factor in the supersonic combustion. In this paper, the influence of the chemical reaction on the development of the supersonic mixing layer is analyzed based on results obtained by the high-solution numerical methods with detailed chemical kinetics. The evolvement of the supersonic mixing layer and the mixing layer thickness under the effect of chemical reaction are analyzed in two different combustion modes. The influence of the chemical reaction on the supersonic mixing layer thickness is explained from the aspect of vertex dynamics.