In order to restore the image in dust environment, a method was proposed to restore the images in dust environment based on a single still image. Firstly, an image degradation model considering multiple scattering factors caused by dust was built using the first-order multiple scattering methods. Then, a new geometric depth model of single image was presented. This model utilized depth map of a dust image to improve usual geometric depth model. According to the new model the every distance of the objects in dust environment was able to acquire from a single still image. Finally, an image in dust environment could be restored according to the relationship between the dark channel prior model and the distance information which was calculated by the geometric depth model. The experimental results have shown that the method enhanced luminance and contrast. The method provided a foundation for target recognition in the dust environments.