Abstract: Based on the large eddy simulation, combined with WENO scheme and the adaptive mesh refinement technique, the supersonic flows of two Mach different numbers ( Ma=2.9, 5.0) past a rectangular cylinder have been simulated. The numerical results revealed that both of the development of the vortex structures in the separation region and the wake vortices variations, and the influences of the Mach numbers on the vortex structures were discussed in detail. The calculated results are in good agreement with corresponding experimental data which can provide important data for related researches.