Abstract: In view of the characteristics of scattered distribution and various operation modes of various electrical equipment in coal mining face at present, a combined switch is used for control. The power supply mode, structure composition, protection system design, control mode design and operation mode design are described and analyzed. Two mobile transformers are used to supply power for one combined switch. CANBUS communication mode is used for the switch, and the switch circuit is simplified. Leakage protection, current protection and voltage protection have high sensitivity and reliability, and they ensure the safety of electrical equipment and operators. According to different electrical equipment and operation requirements, the corresponding start-up mode and control mode can be adopted, and it has good adaptability.