The asymmetric medium distribution of ventilated cavitating will affect their hydrodynamic force and then the cavitating stability control. In recent years， the understanding of the flow characteristics is relatively limited. The flow characteristics of asymmetric ventilated cavity is demonstrated by experimental and numerical methods. The results show that the asymmetric flow leads to the formation of asymmetric wet zone. On the basis of different flow media， asymmetric wetted region can be compartmentalized into transparent gas zone， water vapor mixing zone and wetted zone. As the boundary of water vapor mixing zone develops from incident flow axis to back flow axis， the relatively high pressure decreases， cavity thickness increases， the way that the liquid entering into the cavity is gradually transformed from the axial direction to the circumferential direction， and the area of water vapor mixing increases. In the water-gas mixture flow， with the liquid layer formed along the circumferential direction developing to the back flow axis， a low speed， high pressure and water vapor mixing area is formed at the back flow axis. Furthermore this area has enhanced turbulent characteristics accompanied by large shedding of cavitating vortex.