In recent years, the secure storage and transmission of color images has attracted the attention of scholars. The existing low-dimensional chaotic systems and monotonic DNA coding systems cannot meet the most fundamental requirements of image encryption because of their monotonous structure, low complexity and low security. On this basis, a color image encryption algorithm based on the combination of chaotic system and DNA encoding and decoding is proposed. First encrypt the blocks of the color image, and Then the parameters generated by the Logistic chaotic map are combined with the spatially complex Chen hyperchaotic map, then scramble the 3 channels of the color image R, G, B; Finally, the DNA encoding is used. Encrypt the image messily. At the same time, the number of chaotic systems in the encryption algorithm is increased, and the process of the encryption algorithm is optimized. The improved algorithm is simulated on Matlab 2018b, and the security analysis of the simulation results is carried out through histogram, information entropy and adjacent pixel correlation. The results show that the improved algorithm improves the encryption efficiency of the encryption algorithm and enhances the encryption security.