Abstract: A superhigh frequency nano-tracer planar laser scattering (NPLS) technique has been developed. Based on multi-cavity parallel pulsed laser technology, beam splitting and short-exposure camera integration technology, and high-precision synchronous control technology, MHz-level flow field visualization was realized. The supersonic mixing layer with convective Mach numbers Ma_c=0.17, 0.26 was studied by superhigh frequency NPLS technology. The flow control research was carried out by using the vortex generator array, and a sequence of high-resolution NPLS images of the mixing layer was obtained. The vortex motion and evolution law of the supersonic mixing layer at different stages were analyzed by selecting typical vortex structures. In the instability development stage of the mixing layer, the vortex structure is dominated by translation and rotation, accompanied by stretching; the later section of the mixing layer is dominated by deformation and fragmentation, and a large number of small-scale vortex structures are generated. In addition, small-scale structures will be induced by sheareffects, large-scale structures, and small shock waves, resulting in obvious unsteady motions.