Abstract: Fiber Bragg grating sensors can be applied in the detection environments with high temperature, high pressure, strong corrosion and high explosive hazardous, which can get high accuracy when it measures the parameters such as temperature, pressure and displacement. The number of fiber-optic sensing unit used in a system is less, which resulted in cost of overall system is too high, so reuse technology and the corresponding demodulation technology become the key technology used in fiber optic sensors. The method of introducing the reuse technology of coding can achieve distributed fixed-point measurement of testing areas.