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