The utility model discloses a film type hydrostatic pressure sensor. The film type hydrostatic pressure sensor is characterized by comprising a cylinder composed of a machine cap, a machine body and a bottom cover, wherein the machine cap, the machine body and the bottom cover are connected with each other in a threaded manner; the top of the machine cap is provided with a through hole; the cylinder is separated into two chambers along the axial direction of the cylinder by an elastic film which is arranged on the cross section of the machine body, wherein one chamber is a compressed chamber communicated with a to-be-detected pressure environment, and the other chamber is a detection chamber communicated with air; a modulation plate is arranged in the detection chamber and separated from the elastic film, and a vent is disposed on the modulation plate; a magnetic steel block is arranged in the center of the elastic film; a Hall element is correspondingly arranged on the modulation plate; the Hall element and the magnetic steel block form a Hall sensor; and the Hall detection signals of the Hall sensor serve as output signals of the hydrostatic pressure sensor. The film type hydrostatic pressure sensor adapts to an underwater environment, and enables electric signals to be output directly so as to link online with a computer data process system in real time.