The invention relates to an electronic document authenticity identification system which belongs to the technical fields of computer application, electronic commerce, e-government affairs, information safety and the like. Identification information embedded into an image is generated by a private key generated by a chaotic system and characteristic information of the image through calculation. The identification process can judge whether the image is valid or not by only extracting the characteristic information of the image and calculating with the private key owned by a user without any other information. Because the identification information is generated by the private key through the chaotic system, the system has high safety. Because the identification information is relevant with the height of each pixel in the image, the generated identification image has high sensitivity on falsification. The invention can realize anti-counterfeiting identification on images of electronic scanning images of paper notes, electronic image documents and the like, and has wide application value to the fields of electronic commerce, e-government affairs, and the like.