Abstract: Voltage levels of coal mine power supply system have direct effects on motors′ start-up and normal operation,but now monitoring and control system of coal mine power supply cannot give fore-warning research of running status of coal mine power network and voltage levels using real-time parameters of power network structure and real-time power flow parameters,so it cannot eliminate potential safety problems in power network.Using real-time power flow parameters of monitoring and control system in power network,and combining with analysis hierarchy process(AHP) and fuzzy theory,the paper constructed fuzzy comprehensive evaluation matrix through selecting forewarning evaluation indexes of voltage state and tendency,evaluated current voltage level,analyzed voltage tendency,so as to achieve voltage state and tendency forewarning of coal mine power network,improve and enhance monitoring and control(capabilities) of coal mine power monitoring and control system.