Taking the shape perception and visualization reconstruction of the structure in the spacecraft as the research background, a plate-shaped structure deformation monitoring system based on a quasi-distributed fiber Bragg grating sensor network and a coordinate conversion surface reconstruction algorithm are proposed. First, the finite element analysis software ABAQUS is used to simulate and analyze the deformation state of the four-side fixed plate structure, and the position of the fiber grating sensor is determined. Then, the strain detection principle of the fiber Bragg grating and the three-dimensional surface reconstruction algorithm based on coordinate transformation are studied and analyzed. Finally, a set of deformation detection systems is built, and relevant experiments are carried out. The results show that the root mean square error of the shape variable of the measured point is no more than 0.04 mm, and the relative error is no more than 3.5%. The system can be applied to the deformation detection of the plate structure in the spacecraft.