Study on the bore-sight error (BSE) induced by high-speed flow-field is important for the hit precision of a hit-to-kill interceptor with infrared ray (IR) terminal homing system. Based on the flow-field by solving the thermal-chemistry non-equilibrium Navier-Stokes (N-S) equation, the ray-tracing method is used to calculate the BSE of ray transmission through the flow field outside the optical window. The impact factors of BSE are considered, including incidence angle, Mach number, attack angle, altitude and the IR seeker shape.