Abstract: A method for encrypting color images based on a two-dimensional sine function hyperchaotic map（2D-SFHM） chaotic system and improved DNA encoding is proposed to address the issues of small key space and low-security performance in one-dimensional chaotic systems, as well as the high initial parameter requirements and low efficiency in hyperchaotic system. Initially, chaotic sequences are generated using a 2DSFHM chaotic system and Logistic system. The color image is then divided into RGB channels, and each channel is block-wise encoded, decoded, diffused, and scrambled based on the chaotic sequences and dynamic DNA encoding. Additionally, a gene mutation mechanism is introduced to enrich the DNA encoding rules.Finally, the encrypted color image is obtained by combining the three channels. Experimental results show that the proposed method achieves uniform and smooth statistical characteristics of the ciphertext image histogram, good correlation analysis performance, and effectively secures the encrypted image, demonstrating excellent encryption performance and security.