In order to solve the problems of component deformation and affecting manufacturing quality caused by the residual strain of material components, which is due to the residual stress after hot pressing by the difference of thermal expansion coefficient between resin matrix and carbon fiber in carbon fiber/epoxy resin composite components. The theoretical analysis and experimental verification were carried out by combining the on-line monitoring experimental research of fiber Bragg grating (FBG) sensor and finite element simulation analysis. The real-time data of surface residual strain of carbon fiber/epoxy composite ring components after hot pressing tank forming were collected. The results show that the strain release at the flange root is complex, the residual strain release near the support is blocked, and the residual strain at other monitoring points is generally 30με~90με. The results are consistent with the simulation results. FBG sensor can carry out multi-point real-time on-line monitoring of the residual strain release process after component forming, and realize the analysis and early warning of the overall strain distribution of the component. The research has certain scientific research and engineering application significance.