The invention provides an MEMS (Micro Electro Mechanical System) capacitor film vacuum gauge, which can realize the measurement of the vacuum degree in a range of 1-1000Pa, and the measurement resolution is 0.5 Pa. A pressure sensing film is a circular film with an island-shaped structure film. The circular film is very uniform in radial stress and strain, and under the same pressure, the deflection of the circular film is larger than that of a square film, so that the sensitivity of the pressure sensing film is higher. The island-shaped structure film can increase the rigidity of the film, sothat the deflection of the pressure sensing film is reduced, the basic capacitance is increased, the resolution ratio is improved, and meanwhile, the linearity of the pressure-capacitance relationship is better. Meanwhile, the circular film with the island-shaped structure film is of a double-side electrode differential type sensitive capacitor structure. When the pressure sensing film deforms due to pressure, the sensitive capacitor outputs two capacitances which are equal in variation and opposite in direction, and a double-differential structure is formed through a subsequent differentialmeasurement circuit, so that the common-mode rejection ratio is improved, the influence of parasitic capacitance, temperature and other factors on a measurement result is eliminated, and the measurement resolution is improved.