In order to monitor the deformation state of the deck structure in real time, this paper proposes the inversion method of main beam deformation of jacket platform deck structure based on space curve. The specific ideas are follows: The sparse discrete strain data were collected by the optical fiber strain sensor and converted into curvature data according to the linear relationship between strain and curvature. The continuous curvature data were obtained by interpolation algorithm, integrated segment by segment and recurred to obtain the position coordinates of the end points of each micro-segment. Finally, the continuous space curve is fitted to achieve the structural deformation inversion. Furthermore, the bidirectional recursion strategy is proposed to eliminate recursion cumulative error and end temperature difference during calculation. Based on ANSYS software, a numerical simulation model of the deck main beam structure on the deck of a conduit jacket platform is established and the effectiveness of the deformation inversion algorithm is verified through numerical analysis. The inversion results show that the maximum relative error is less than 3% when the interval of measuring points is 1/10 of the model length, which verifies the validity of the inversion method based on space curve. Compared with the unidirectional recursive calculation method，the error elimination of the bidirectional recursive calculation method is more remarkable and can be reduced by more than 50% when the distance between measuring points is 1/8 of the model length. Based on the measured strain data of a jacket platform in Chengdao Oilfield and the deformation inversion algorithm, the deformation range of the main beam is -10mm to 10mm, the deformation assignment is relatively small, and the structure is in safe operation. The relevant research conclusions can provide important reference for the deformation inversion of the main beam of the deck structure of jacket platform.