Abstract: The paper analyzed disadvantages of automatic power off of monitoring and control of local ventilator combining with practical working experiences,discussed unconformity between automatic power off of monitoring and control of local ventilator and relative regulations of coal mine safety regulation,and made the conclusion that automatic power off of monitoring and control of local ventilator may make power off not thorough,difficulties in electrical maintenance,increasing circuit complexity,independence in main and spared local ventilator,and expanding disasters scope,namely which is more unbenefited.The paper is attached with detailed graph,helpful for practical operation.