A system for fiber DC magneto-optic detection and method thereof are provided. The system comprises a power supply and signal processing module (400), an optical fiber device (200), a magneto-optic probe (100) and a reference device (300). The reference device (300) is mounted in the system, and the measured signal can be corrected via a reference magnetic field pulse signal generated by the reference device (300) so as to eliminate the influence that the environmental factors caused on the measurement, and to obtain accurate measurement data, thus improving measurement accuracy of the system.