Abstract: Embodiments of the present disclosure provides an absolute pressure sensing MEMS microphone, a microphone unit and an electronic device. The absolute pressure sensing MEMS microphone includes: a diaphragm; a back electrode plate; a spacer between the diaphragm and the back electrode plate, wherein the diaphragm, the back electrode plate and the spacer form a vacuum cavity, an air pressure in the vacuum cavity is a first air pressure, wherein a gap separating the diaphragm from the back electrode plate by the spacer is a fabrication gap, wherein in a state where the air pressure inside and outside the diaphragm are both the first air pressure, an effective vacuum gap between the diaphragm and the back electrode plate is the first vacuum gap, and wherein the first vacuum gap is larger than the fabrication gap.