The invention relates to the field of electronic technology, and more particularly, to a microphone structure. A MEMS (Micro-Electro-Mechanical System)-based bone conduction sensor comprises: a closed cavity within which a uniaxial or biaxial accelerometer sensor is arranged to be adjacent to bones of a human ear; an ASIC (application-specific integrated circuit) processing chip coupled to the uniaxial or biaxial accelerometer sensor, the ASIC processing chip being provided with an output end for a vibration signal. By adopting the above-mentioned technical solution, a bone conduction sensor with a closed cavity is provided in the present invention. Furthermore, a uniaxial or biaxial accelerometer sensor and an ASIC processing chip are arranged inside the closed cavity. In this way, the production costs are reduced, and interference of the sensor caused by ambient environment is reduced.