The utility model relates to a multichannel power frequency magnetic field intensity synchronous measurement system, the system includes: the next machine, its and upper computer connection for carryout communication and data transmission with the host computer, the host computer, it links to each other with the next machine for send to the next machine according to sampling interval and read data command, and the measured data who sends the next machine gathers, demonstration, storage, assay and warning, a plurality of power frequency magnetic field intensity measuring unit, it is used for measuring the power frequency magnetic field intensity of power frequency magnetic field intensity measuring unit present position to, power frequency magnetic field intensity value sends alarm signalwhen exceeding the value of setting. The system adopt wireless communication technique and multichannel measuring technique, but measurement power frequency magnetic field intensity's needs are arranged to the multiple spot fully provided transformer substation in, have practiced thrift the communication cost that lays wire, have improved work efficiency and security, have reduced intensity of labour.