The invention discloses a MEMS microphone. The MEMS microphone comprises a first substrate and a vibrating diaphragm supported above the first substrate through an interval part, the first substrate,the interval part and the vibrating diaphragm form a vacuum cavity; the static deflection distance of the vibrating diaphragm under the atmosphere pressure is less than the distance between the vibrating diaphragm and the first substrate; a magnetic film is arranged on one of the vibrating diaphragm and the first substrate, and a reluctance sensor matched with a magnetic film on the other one; thereluctance sensor is configured to sense magnetic field change of the magnetic film in the vibration process of the vibrating diaphragm, thereby outputting the changed electric signal. Through the MEMS microphone disclosed by the invention, the signal to noise ratio of the microphone is improved, and the whole size of the MEMS microphone is greatly reduced.