Abstract: The paper introduced working principle and design of hardware and software of double local-fans automatic switching system of underground working face. The system is consisted of main circuit and switching control circuit, uses PIC microcontroller as control core, and detects information of air volume through wind speed sensor. When there is ventilation failure or electrical failure, the switching control circuit sends switching signal to the main circuit, then the main circuit switches to make the main ventilator stop working and the backup one start working, thus ensures continuous ventilation. The system can reduce unplanned off-blast of underground heading face, further ensure safety of underground production, and improve work efficiency.