The invention provides an angular speed measuring method and device based on a photoelectric oscillator. The device comprises a light source, a first polarization controller, an electrooptical modulator, an Sagnac interferometer, a photoelectric detector, a band filter, a microwave amplifier and a power divider, wherein the Sagnac interferometer comprises an optical circulator, a second polarization controller, a light beam splitter, a Sagnac ring, a rotating table and a polarizer. The method comprises the steps: measuring the frequency fosc of an oscillator signal output by the powder divider when the Sagnac ring is static, measuring the frequency f'osc of an oscillator signal output by the powder divider when the Sagnac ring rotates at the angular speed omega, and calculating the angular speed omega based on the fosc, the f'osc and the parameters of the loop circuit of the photoelectric oscillator. According to the angular speed measuring method and device based on the photoelectric oscillator, the Sagnac ring is embedded into the photoelectric oscillator, the phase change of the Sagnac ring resulted from the angular speed omega is mapped to the oscillation frequency change of the photoelectric oscillator, and simultaneously, the advantages of high-quality microwave signals produced by the photoelectric oscillator and high-resolution microwave measurement are combined, thereby greatly improving the sensitivity and resolution in measuring the angular speed omega.