The utility model relates to a silicon controlled rectifier synchronization signal's system that acquires in magnetic control reactor, including the magnetic control reactor, the magnetic control reactor includes the iron core, on the iron core coiling have with the magnetic control reactor in the insulating coil of high -pressure system, it is connected with voltage detector to take a percentage for two of the coil, voltage detector is connected with the treater, the trigger control module of thyristor is connected in treater and the magnetic control reactor. Voltage detector induction coil both ends voltage is fit for the synchronizing voltage as the thyristor, the simple structure of this system, and cost economy, convenient to use, and it is good to obtain the synchronizing voltage degree of accuracy.