Abstract: According to the situation that the two sets of air door of a coal mine can not switch in position in manual operation, and it is likely to cause accidents, we propose three solutions and use high speed counter module FM350 and E6B2-CWZ6C incremental rotary encoder to achieve the air door's automatic control. The field application shows that the system is stable and the air door can switch in position. This automatic control system has the characteristics of convenient operation, safety and reliability. It eliminates the safety risk in the process of coal production, and greatly improves the production efficiency of coal mine enterprises.