By using the separated eddy simulation (DES) and the fluid software as the research tool, the steady and transient simulation and analysis of the external flow field are carried out under the closed window condition in the rear-view mirror area of a vehicle. The pressure fluctuation on the body surface, which is used as the excitation to calculate the interior noise of the vehicle, is obtained. The coupling analysis of flow field and acoustic field around the rear-view mirror is realized by using acoustic software, and then the spectrum of sound pressure level is obtained. By analyzing the aeroacoustic characteristics of the internal and external fields of the basic model and the improved model, it is shown that the length of the rear-view mirror handle, the angle between the mirror handle and the mirror cover, and the shape of the mirror cover have great influence on the downstream flow field and the sound pressure level of the rear-view mirror. Compared with the basic model, the total sound pressure level on the outer surface of the front left-side windscreen of the improved model is reduced; the total sound pressure level in the inner field of the driver’s left ear is reduced by 6.41%, and the speech intelligibility is improved by 33.89%.