The invention relates to an image encryption algorithm based on memoristor hyper-chaotic system, cellular automaton and DNA calculation. First of all, a four-dimensional memoristor hyper-chaotic system based on a Chua circuit is employed, at the same time, a secret key is generated by enabling a plaintext image on an SHA256 function; a pseudo random sequence generated by the chaos system is taken as a basis of DNA dynamic encoding, rules of cellular dynamic evolution are determined according to a DNA matrix after diffusion, and in an encryption process, partitioning processing is performed on the image; and finally, the image is encrypted through a pseudo DNA calculation method, and diffusion operation is carried out while the image is scrambled. According to the invention, on one hand, secret key space is increased and the capability of the algorithm in fending off violent attacks is enhanced; and on the other hand, the secret key is enabled to be generated through close reliance on a plaintext, the capability of the algorithm in fending off plaintext attacks is improved, the capability of fending off exhausive attacks is higher, parallel calculation is facilitated, the operation efficiency is further improved, and the security of the algorithm is improved.