The invention discloses a pressure sensor which comprises a substrate, a film, a permanent magnet, metal coils and a conductor cantilever beam; the permanent magnet is fixedly connected to the bottom side of the substrate, the upper portion of the substrate is provided with a cavity, and the film grows in the top side of the substrate, and covers the upper of the cavity; and the metal coils are fixedly connected to the top side of the film, and the conductor cantilever beam is fixedly connected to the top side of the substrate, and positioned over the metal coils. The pressure sensor is simple in structure, pressure is measured by utilizing the electromagnetic principles, and the process is simple. The invention also provides a working method of the pressure sensor, and the method is easy to realize.