In order to monitor the deformation of transformer windings, wings, bridges and other equipment or engineering structures, the distributed optical fiber sensing system based on optical frequency domain reflection(OFDR) is used to study deformation reconstruction in this paper. Firstly, the transformation relationship between strain and curvature is introduced, and then the curve deformation reconstruction based on tangent recursive algorithm is deduced, and the improvement of reconstruction algorithm is proposed on the basis of tangent recursive algorithm. In the experiment, the spatial resolution of OFDR strain measurement system is set to 2 cm, and the concentrated force is loaded in the middle of the simple beam. When the concentrated load is 11.76 N, the maximum deformation reaches 40 mm. After eliminating the system error, the maximum error of the tangent recursive algorithm is 0.667 mm, and the maximum error of the improved reconstruction algorithm is 0.59 mm.