Pressure sensor, preparation method thereof and chip

The embodiment of the invention provides a pressure sensor, a preparation method thereof and a chip. The pressure sensor includes a measurement capacitance and a reference capacitance. The measuring capacitor comprises a first substrate and a second substrate which are stacked, and the first substrate and the second substrate enclose to form a vacuum first chamber; one side, facing the first cavity, of the first substrate comprises a first measuring pole plate, one side, facing the first cavity, of the second substrate comprises a second measuring pole plate, and the capacitance of the measuring capacitor changes along with external air pressure; the reference capacitor comprises a third substrate and a fourth substrate which are stacked, and the third substrate and the fourth substrate enclose to form a second cavity; the side, facing the second cavity, of the third substrate comprises a first reference pole plate, the side, facing the second cavity, of the fourth substrate comprises a second reference pole