The shock wave around blunt is simulated numerically by solving three-dimensional Euler equations with Godunov stiucture mesh method Taking into account density and pressure distribution, the flow field is divided into uniformity. inhomogeneity and shock wave layer. When optical beam passes the shock wave of high pressure and density come into being supersonic vehicle front, the refraction is calculated numerically. The results show that the refraction is influenced largely by shock wave. It is efficient to amend refraction by simulating flow field.