For researching aerodynamic heating of a certain type of medium-range ballistic missile's nose fairing in its working time, a turbulence model was used to solve Navier-Stokes equation. The aerodynamic heating conditions of ballistic missiles nose fairing during working time was calculated and analyzed. The rule that temperature, heat flux are changing with speed was obtained. Results shows that the temperature increases with the augment of the speed and altitude of missile, the max heat flux appears at the speed of Mach 5, stagnation point positions at the front end of nose fairing.