Located in Dunhuang, northwest China, the Mogao Grottoes are a cultural treasure of China and the world. However, after more than 2,000 years of weathering and destruction, many murals faded and were damaged. This treasure of human art is in danger. Mural inpainting through deep learning can permanently preserve mural information. In order to reduce manpower and material resources, the efficiency of mural image restoration is significantly improved. Therefore, a digital restoration method combining Deformable Convolution (DCN), ECANet, ResNet and Cycle Generative Adversarial Network (CycleGAN) is proposed. We name it DC-CycleGAN. Compared with other image digital inpainting methods, the proposed DC-CycleGAN based mural image color inpainting method has better inpainting effects and higher model performance, which can better capture the high-frequency characteristics of the image and avoid network degradation and gradient disappearance. The digital restoration of mural images provides a new theoretical and scientific basis for the protection and restoration process of murals, and shows the latest attempts of mural restoration.