Abstract: An encryption approach based on cross-coupling chaotic system is proposed.In this algorithm，a new logistic model of cross-coupling is defined.This cross-coupling chaotic system can produce two groups of sequences at the same time.One is used to shuffle the images，and the other to encrypt the image information by changing the grey values of the pixels.The difference between this algorithm and the present one lies in the fact that the former uses one chaotic system to shuffle and encrypt at the same time while the latter uses two separate chaotic systems to shuffle and encrypt respectively.Simulation results and security analysis show that this improved algorithm，which can widen the key space，is of greater security and of less time complexity.