An MEMS capacitor microphone is provided, comprising a first substrate and a vibration diaphragm supported above the first substrate by a spacing portion, the first substrate, the spacing portion, and the vibration diaphragm enclosing a vacuum chamber, and a static deflection distance of the vibration diaphragm under an atmospheric pressure being less than a distance between the vibration diaphragm and the first substrate, wherein a lower electrode forming a capacitor structure with the vibration diaphragm is provided on a side of the first substrate that is adjacent to the vacuum chamber, and an electric field between the vibration diaphragm and the lower electrode is 100-300 V/μm.