Inflatable antenna is a potential technique for large space deployable antenna and knowing its reflector’s deformation behavior is quite important for its accuracy improvement. A 1.5m-diameter inflatable reflector’s deformations at different internal pressures are studied using digital image correlation(DIC) in the paper. Because of the symmetry of the reflector, only two representative gores on the reflector are chosen to study. During the digital image correlation measurement, some article random dot patterns are drawn on the reflector’s surface. The 2D and 3D displacement maps of the reflector at different internal pressures are gained by DIC measurement and the cross-section of one gore of the reflector according to the internal pressure are analyzed from the measurement results.