Abstract: In order to improve the effect of two-dimensional image encryption, the pixel scrambling and pixel are proposed to replace a combination of two methods to realize image encryption. In the first place, by using the bit-plane decomposition, the plaintext image was processed, and then the pixel scrambling encryption was preprocessed for the eight bit planes respectively by using the magic square transform scrambling method, and then the hyperchaotic sequence generated by the fifth-order cellular neural network (CNN) hyperchaotic system was used to encrypt the pixel replacement of the four higher level planes, and the algorithm of information entropy can reach 7.986. This embodied the high randomness. At the same time, the method can change the histogram of encrypted image and reduce the correlation between pixels, which can effectively improve the encryption effect and anti-attack ability of two-dimensional image.