Abstract: In view of the problem of lack of gas drainage concentration control and the high energy consumption of the water ring vacuum pump in the extensive control method of existing coal mine gas drainage control, a coal mine gas drainage concentration control system was designed. The system is based on the hierarchical adjustment idea, and under the centralized control of the control program, the gas concentration in the extraction pipeline is detected by the gas concentration sensor, the gas concentration change rate is calculated by the PLC logic operation function, and then the opening degree of electric gas control valve and the variable frequency motor speed of water ring vacuum pump are adjusted by grade according to the change of gas concentration to increase the concentration of gas extracted, so as to improve utilization rate of the extraction gas. The test results show that the control system can effectively increase the gas concentration of the extraction, and the gas concentration can be increased by 3.6%-4.2%, which greatly improves the gas utilization rate of the extraction. And the energy saving effect is obvious, the energy saving effect is improved by 24% after the gas drainage concentration control.