Abstract It is possible that the shaded area was mistakenly identified based on digital images processing technology with non-uniform illumination. The binarization algorithm of two-dimensional code was optimized to this problem. The local area threshold of the image and the pixel-by pixel sliding calculation are used to eliminate the influence of the illumination on the image, thereby improving the recognition rate of the two-dimensional code image which contains the shadow. Experimental result indicate that the method has a stronger adaptability to images with shaded areas, especially for unilateral shadows which are less ideal for block resolution. Compared with the classical global Ostu algorithm, the recognition rate of the image is increased by about 3 times.