Abstract: IDDES coupled with J-B model and dual time step LU-SGS method has been adopted to carry out numerical simulation research on unsteady aerodynamic loads on a turret. Flow around the turret will separate, and the separation angle at the zenith is greater than 90°. When the flow bypasses the turret, unsteady flow field structures such as horseshoe vortex and shedding vortex street will form, resulting in unsteady aerodynamic loads. Power spectral density of pulsating static pressure at the zenith lies in the inertial sub-region of isotropic and uniform turbulence at 1.6-40.0 kHz, which basically satisfies Kolmogrov’s −5/3 law. Aerodynamic force is mainly drag force, fluctuation amplitude of transverse force is large, while aerodynamic moment is mainly pitching moment, fluctuation amplitude of rolling moment is also large, but yaw moment can be ignored. The power spectra of aerodynamic force and moment are mainly concentrated below 1 kHz, there are obvious peak frequencies, and the dominant frequency is about 230 Hz (Strouhal number is 0.15). At the beginning of the design of the acquisition tracking pointing (ATP) system, unsteady characteristics of aerodynamic loads on the turret should be considered, and resonant failure problem caused by peak frequencies, especially the dominant frequency, should be avoided.