Reflectance Confocal Microscopy for skin(RCM) is an important skin imaging diagnostic tool, which uses resonant galvanometer that will result in nonlinear distortion at image. In order to correct the distortion, a method of anti-sine signal oversampling based pixel using isochronous sampling system to correct the distorted RCM image caused by resonant galvanometer was presented. The results of experiments on the rectangular grating with a pitch of 20 μm indicate that, the standard deviation of the grating spacing is 7.78 μm. The distortion rate of image before being corrected is 38.9%. The standard deviation of the image corrected by the anti-sine signal over-sampling based pixel method is 0.85 μm, so the distortion rate is reduced to 4.2%. According to the results of a resolution plate and the actual human skin imaging, the distortion correction method proposed in this paper can correct the image distortion caused by resonant galvanometer and meet the human skin real-time non-invasive imaging diagnostic requirements.