Aiming at the problems of small chaotic space and weak chaotic ability of existing chaotic mapping models, a new two-dimensional chaotic mapping model is designed by coupling two-dimensional Henon chaotic mapping model and Sine chaotic mapping model. A new one-dimensional chaotic mapping model is designed by coupling Sine chaotic mapping model and Logistic chaotic mapping model. To solve the problem of low security when using single scrambling method for image encryption, a randomly selected scrambling algorithm is designed by using Lorenz mapping. A color image encryption scheme is proposed using two chaotic mapping and scrambling selection methods designed in this paper. The experimental results show that this method has a large scrambling range, high security, good image encryption effect, strong resistance to common attacks, and it is easy to implement.