The work aims to solve the problem of chaotic performance degradation of chaotic sequences as encryption algorithm cannot better resist the attacks of chosen plaintext. An image encryption algorithm based on variable parameters was proposed. The proposed algorithm used cipher feedback mode to encrypt the plaintext block sequentially. In the diffusion part, a conventional bitwise XOR diffusion method was abandoned, and a block-by-block ectopic XOR algorithm was proposed. The simulation results showed that, the proposed algorithm was sensitive to the key, and the NPCR values of the test subjects were respectively 99.59%, 99.61%, and 99.61%. UACI values were respectively 33.44%, 33.46% and 33.45%, and the information entropies were 7.9872, 7.9989 and 7.9977, respectively. Compared with other similar algorithms, the proposed algorithm had better comprehensive effects. The key space was (1016)6+1014×9. The ciphertext is sensitive to plaintext, and can resist the chosen plaintext attacks. The proposed algorithm not only solves the problem effectively, but also has high security performance.