Results of an experimental study of the supersonic mixing layer are reported, concerning the evolution characteristics of the vortex structures. Experiments are conducted in a supersonic mixing wind tunnel with a convective Mach number of 0.17. The superhigh frequency Nano-tracer Planar Laser Scattering (NPLS) technique is applied to visualize the flow patterns. The first time the spatial and temporal evolution characteristics of the vortex structures are captured. For the supersonic mixing layer, the initial section is dominated by translation, tension and rotation, while the rear section is dominated by mixing, blending and crushing.