Abstract: A sub-pixel displacement measurement method based on a Tikhonov regularization, including the following steps: collecting two images before a structure is deformed, and recording the two images as reference images; collecting an image after the structure is deformed, and recording the image as a target image; extracting grayscale matrices in the two reference images, recording the grayscale matrices as f0 and f1, and calculating a noise level parameter ? of the two reference images: taking a pixel point to be measured as a center point, extracting a square region in the target image, recording a grayscale matrix of the square region as g, and using a Tikhonov regularization method to separately obtain grayscale gradient matrices of the square region along an x direction and along a y direction; and calculating a sub-pixel displacement of the structure by using the grayscale gradient matrices.