Abstract: Color image is more widely used than gray image in social network, and it contains a large amount of information. These factors make the encryption algorithm to face a greater challenge. In order to improve the encryption and decryption efficiency of color images and protect the privacy information from being disclosed, a color image encryption algorithm based on Chinese remainder theorem and Logistic map is proposed. The pixel values of color images are compressed and diffused by Chinese remainder theorem, then the pixel positions of the images are further scrambled by Logistic map, combining with the plaintext image information and the pseudo-randomness of chaotic map. Simulation results show that the algorithm has high encryption efficiency and good security performance.