Abstract: In view of the storage characteristic of color images, in order to extend the effect and security of image encryption algorithm.A color image encryption algorithm based on the three-dimension chaotic system was proposed.Firstly, the chaotic sequence were adopted by the three-dimension chaotic system.Then a color image was encrypted in space domain by using composite encryption algorithm.Using MATALAB7.0 carried out simulation.Theoretical analysis and simulated experiment show that, algorithm guarantees the security of the encryption effectively and excellent effect of encryption.If reduces the computation, the algorithm can be used widely in military satellite images, trade secret drawings, long-range private medical that wanted to be kept confidential communications.