The operating bandwidth and transmission loss of optical fiber are wide and low. Micro-electro mechanical system (MEMS) manufacturing process can achieve miniaturization, mass production, and high consistency. By combining the above two advantages, MEMS optical acoustic sensors exhibit excellent acoustic detection performance with high sensitivity, wide frequency band, large dynamic range, and high signal-to-noise ratio, which has attracted widespread attention and in-depth research by researchers. According to the different structures of acoustic sensing units, MEMS optical acoustic sensors are divided into micro-structured fiber grating types, fiber interferometer types, and micro-resonator types. The sound detection principle of different MEMS optical acoustic sensors are introduced, respectively. Then their research status in the field of different sound detections and the most mature application fields of them are discussed. Finally, the future development trend of MEMS optical acoustic sensors, which can be combined with silicon-based optoelectronic integration technology to realize system on-chip integration, is prospected.