The two-dimensional barcode / two-dimensional code (2-dimensional bar code) is the symbol information of the black and white images that are distributed in a plane (two-dimensional direction) in a certain geometric pattern. The concept of "0" and "1" bit stream, which constitutes the internal logic base of the computer, is skillfully used in the code compilation. Using a number of geometric forms corresponding to the binary to represent numeric information, automatically read through an image input device or a photoelectric scanning device to achieve automatic information processing: it has some commonalities in barcode technology: each code has its specific character set; each character occupies a certain width; it has a certain degree of correction. Test function and so on. At the same time, it also has the function of automatic recognition of information from different peers, and processing the change point of graphics rotation.