Abstract: Shock wave boundary layer interaction prefers to induce boundary layer separation, and it's necessary to analyze the flow structure, local high pressures and heat flux, and the separation bubble size. In this paper, we propose an analytical model for this typical flow structure, and the polar theory is used for auxiliary analysis. Based on the FIT, classical shock relationship, and fitting formula of separation length, the analytical model can be solved. With the analytical model, we can quickly gain the flow structure and parameters which compares well with numerical simulation. Also, we use this model to analyze the height of separation bubble. The height increases with increasing flight altitude and deflection angle for incident shock wave, and it first decreases slightly then increases as incoming Mach number increases.