Abstract: A high sensitivity fiber-optic microphone based on Fabry-Perot interferometer was studied systemically and comprehensively, including Fabry-Perot interferometer, light intensity demodulation and voltage output. According to the analysis and calculation of basic principles, a fiber-optic microphone was realized and manufactured with a sensor cell of compact structure, a coherent light source of optional assembly by amplified spontaneous emission (ASE) broadband light source and dense wavelength division multiplexing (DWDM), and electric circuits of transimpedance amplifier and pre-amplifier. The performance of the fiber-optic microphone was characterized. The results show the high sensitivity of 247 mV/Pa, frequency range of 30 Hz~4 kHz with conformity less than 2 dB, and high SNR and low total harmonic distortion.