In order to improve the fiber Bragg grating strain measurement range and measurement accuracy,the strain transfer theory and finite element analysis of stress distribution of substrate type optical fiber grating sensor was discussed in this paper,and the fabrication process of fiber grating strain sensor was investigated.The difference between the encapsulation technology and common substrate optical fiber grating sensor was that the certain pretightening force was loaded during the production process.The measurement and calibration of the prestress substrate fiber Grating sensor was carried out by the equal strength beam.The sensor sensitivity of 0.88 pm/με,linearity of 0.996,and transfer efficiency of 74% were obtained.The comparative experimental study on the substrate pretightening fiber Bragg grating sensor,bare optical fiber grating sensor and the resistance strain gauge compression was carried out on MTS.The results showed that the prestretching process improved the linearity and measurement range of the fiber Bragg grating measuring compressive strain.