A method for inhibiting zero drift of an all-fiber interferometric fiber optic gyroscope and a corresponding all-fiber interferometric fiber optic gyroscope are disclosed. The method comprises: reversing the polarity of an AC voltage applied to a PZT piezoelectric ceramic phase modulator according to a predetermined half-cycle time period, and making half of the difference between output rotation rates of the gyroscope in two adjacent half-cycle time periods as the output rotation rate of the gyroscope in a cycle. A phase reversal switch and a DSP chip are added to the all-fiber interferometric fiber optic gyroscope. The phase reversal switch is used for controlling the polarity of the AC voltage, and the DSP chip is used for outputting a square wave signal to control the phase reversal switch and for calculating the output rotation rate of the gyroscope according to the output signal of a demodulation/amplifier circuit.