The present invention provides an acoustic-magnetic synchronous measurement type distributed optical fiber sensing system. The system comprises an acoustic-magnetic synchronous measurement type probe array. The acoustic-magnetic synchronous measurement type probe array comprises a sensing optical fiber used for acquiring an external acoustic-magnetic signal, and stretching the signal to change the variation of the optical index of the signal, a distributed optical fiber sensing demodulation instrument connected with the acoustic-magnetic synchronous measurement type probe array and used for sending optical pulses to the sensing optical fiber and receiving the reflected light of the sensing optical fiber and demodulating the phase of the reflected light. The reflected light is the reflected light of the optical signal obtained through subjecting the optical pulses to the action of the acoustic-magnetic signal. The acoustic-magnetic synchronous measurement type distributed optical fiber sensing system can detect underwater sound signals and magnetic field signals at the same time, and has the advantages of high pressure resistance, high precision, multi parameters, real-time measurement and the like. Therefore, the system can be better applied in the practical engineering field.