The invention discloses an interferometric fiber-optic gyroscope capable of eliminating spike. An optical path part comprises a light source, a beam splitter, a Y-shaped branch, a sensitive fiber coil, a detector and an auxiliary detector, and a light intensity control unit for eliminating spike light intensity is arranged between the beam splitter and the detector; and an electric circuit part comprises an intensity noise inhibition unit, a logic control and operation unit and a power feedback control unit, an output end of the logic control and operation unit is connected to the light intensity control unit by a logic switch, and when spike is produced, the logic control and operation unit starts the light intensity control unit by the logic switch and through the light intensity control unit, light intensity of the spike is attenuated to a preset value. The interferometric fiber-optic gyroscope realizes signal light intensity adjustment in a light test signal stage, eliminates spike produced by fiber-optic gyroscope working point reciprocating, and improves fiber-optic gyroscope actual-measurement precision and environmental suitability.