The vortices inside mixing layers impose remarkable aero-optical distortions on a beam even at moderate subsonic speeds. Knowledge about aero-optical effects caused by vortices in the flow field, especially their spatial and temporal evolution, is limited for supersonic mixing layers because the flows have very high speeds. In this paper, the temporal evolution of aero-optical effects caused by vortices in the supersonic mixing layer was investigated. A large eddy simulation was used to simulate the supersonic flow. A novel approach, coordinate extraction of vortex core, which is based on the relationship between vortices and the profile of the optical path length over the flow field, was proposed to quantitatively calculate the radii and convective speeds of vortices. A model used to quantitatively describe the temporal evolution of aero-optical effects caused by vortices in the supersonic mixing layer was developed and validated with data of numerical calculation. The results indicated that the model is available. Finally, several conclusions drawn from this work were presented.