In order to measure the radial distortion in optical imaging system, a new method based on carrier-fringe pattern phase analysis using dilating Gabor transform was presented, and measuring radial distortion was converted into measuring modulated phase. Firstly, a deformed grating pattern (namely a distorted image) was obtained from a vertical original grating pattern by the optical imaging system. Then, the dilating Gabor transform was used to extract the fundamental frequency and phase at the central point of the deformed pattern, where there was no distortion, and the fundamental frequency information was the fundamental frequency component of an ideal image. The deformed grating pattern was analyzed by use of the dilating Gabor transform, and the modulated phase distribution, which was used to calculate the radial distortion distribution, was obtained. Finally, by use of the above radial distortion distribution and bilinearity interpolation, the corrected image was reconstructed. Detailed theoretical analysis is presented and experimental results demonstrate the validity of the above method.