Bottom water coning is the most common problem in the development of bottomwater reservoirs in horizontal wells. It seriously affects the production efficiency of horizontal wells and produces gas. In severe cases, “flooding” may even occur. Adaptive Inflow Control Device (AICD) is an important structure that can effectively control bottom water coning and improve the economic benefits of horizontal wells. Based on the fluid simulation software STARCCM+, this paper analyzes the new AICD and finds that the angle of the Yshaped flow deflector has a great influence on the pressure drop of the oil phase. Decreasing the included angle will effectively reduce the pressure drop of the oil phase and ensure that the pressure drop of the water phase is maintained at a higher level. The optimal AICD’s oil control capacity is at 35°of the angle of the Yshaped flow deflector. The use of countercurrent flow channels for the first time significantly increased AICD’s ability to stabilize oil and control water. The pressure drop in the water phase reached 0.748 MPa, and the water pressure drop ratio was 3.234.