Electric power system optical fiber line state on -line measuring equipment, relate to the electric power system fiber communication field, the current optical fiber line management equipment of solution has the error detection difficulty and row hinders chronicly and can not satisfy optical fiber line intelligent management, do not have and freely switch between many mode and lead to monitoring the dumb, do not provide special monitoring mode and lead to the little scheduling problem of equipment suitable environment scope specific circuit, including a n the same detecting element, every detecting element includes first photoswitch, the second photoswitch, spectrometer and optical power meter, a n the same detecting element shared control unit, OTDR, the third photoswitch, report an emergency and ask for help or increased vigilance module and server, every detecting element corresponds an optical fiber line, and every unit has work optical fiber detection mode, reserve optical fiber detection mode and the non - detection mode of optic fibre, and switches each other between each mode, and this is novel has eliminated because of using the wavelength division multiplexer drawbacks such as optical wavelength restriction that lead to communicating, has satisfied the demand of multiple optical fiber line management.