Pressure sensors are devices that can feel pressure signals and convert pressure signals into usable output electrical signal according to certain principles. Pressure sensors are usually consisted of pressure sensing elements and signal processing units. In terms of pressure types by different tests, pressure sensors can be divided into gauge pressure sensors, differential pressure sensors and absolute pressure sensors. Pressure sensors are the most commonly used sensors in industrial practice, so they are broadly used in a variety of industrial automation environment, involving water conservancy and hydropower, railway transportation, intelligent building, production automation, aerospace and other industries.