Rearview mirror is an important source of aerodynamic noise in the front window area of the car. It is of great significance to study the characteristics of the wake of rearview mirror to understand the mechanism of aerodynamic noise of rearview mirror. The wind tunnel test platform was built to measure the time-averaged and instantaneous wake of the rearview mirror bluff body by surface oil streamline, hot wire anemometer, and Particle Image Velocimetry（PIV）. Proper Orthogonal Decomposition（POD） was used to identify the large-scale coherent structures in the wake of the rearview mirror. The experimental results show that, due to the finite length feature, the wake of the rearview mirror is similar to that of the finite-length cylinder. Alternating vortex shedding exists in the wake, whose characteristic frequency is less than 0.2. Under the influence of the downwash airflow at the top end, the characteristic frequency of the vortex shedding is unevenly distributed in the streamwise direction and the spanwise direction. The POD analysis results verify the existence of alternating vortex shedding, which leads to the streamwise and spanwise oscillation of the wake recirculation zone. Therefore, the wake of the rearview mirror is similar to that of the finite length cylinder, and the wake vortex shedding is mainly affected by the finite length characteristics.