In order to overcome non-uniformity defects arisen from image vignetting captured by a camera in the dot-to-dot correction of a LED display panel, a correction method based on an image smoothing filter algorithm was proposed from the gray distribution rule of vignetting images. Firstly,the imaging principle of CCD on the optical data acquisition in the LED display panel was discussed. Then, the principle of smoothing filter in the spatial domain was described based on the analysis of the stability of CCD imaging, and the surface of the image vignetting defect distribution was obtained by a neighborhood average process to the spatial distribution of LED pixels. Finally, the algorithm to complete the correction of image vignetting by using the surface was presented. Experimental result indicates that the display uniformity deviation of the LED display panel is narrowed from 12.9% to 0.73% after the calibration for the image vignetting, which overcomes the “Center dark, Surroundbright” defects on LED display panels and achieves the desired effect.