Abstract:A kind of selfgain optical fiber differential pressure sensor based on damping piston is studied. Firstly, the structure of the sensor probe based on the damping piston was put forward, and the design of the sensor system was also presented. Then the theoretical study of the sensor was carried out, the intensity compensation model, the intensity modulation function and the sensing model of the sensor were established, and the simulation experiment was carried out based on the theoretical model. At last, the experiment was carried out by using the experimental prototype. The experimental results show that: in different design dimensions, the sensor has different measuring range, and the sensor has better sensitivity and linearity, the output value can be achieved selfgain. The research shows that the optical fiber differential pressure sensor has better detection performance and can meet the needs of different detection occasions.