Calculation of the acoustics noise is divided into calculation of flow field and acoustic field based on the acoustic analogy theory. Numerical simulation of aeroacoustics noise caused by a kind of SUV vehicle rear-view mirror is finished by combining calculation of flow field step by step in complete domain & subdomain with calculation of acoustics field by ACTRAN. The simulation results of aeroacoustics noise caused by the rear-view mirror are well consistent with the experimental results. The accuracy and reliability of numerical simulation method is verified. The aeroacoustics noises caused by the optimized rear-view mirrors are simulated with this method. The contours of external flow field, internal & external acoustics field and the curves of sound pressure level spectrum of the vehicle are obtained. The outflow field turbulent fluctuation pressure, the vortex and the distribution location of the sound source are improved in the scheme Ⅲ of the rear-view mirror by analyzing the variation rule of flow field contour and the spectrum curve of acoustics field. The aeroacoustics noise propagated into cabin through the side window is weakened. The distribution of internal acoustics field in cabin is optimized and the comfortability of driver and passengers is improved.