Abstract: The effects of control rod on the characteristic of the closed cavity flow and the sound pressure level (SPL) along the cavity bottom wall were investigated by means of the numerical simulation and wind tunnel test. Closed cavity flow was simulated by solving the 3D Favre-averaged Navier-Stokes equations using AUSM+ schemes and Wilcox k-ω turbulence model. The experiments were conducted in the supersonic wind tunnel with cross section of 0.6m×0.6m. The model was instrumented with 40 static pressure orifices and 15 dynamic pressure orifices. It was obtained that the closed cavity flow produces a strong adverse static pressure gradient over the cavity flow in supersonic flow, and there are not obvious peaks on the spectrum of the SPL. When the control rod is introduced, the longitudinal static pressure gradient becomes weaker along the bottom wall, and the spectrum of SPL near the front separation region of the cavity is increased and the spectrum of SPL near the rear separation region of the cavity is reduced.