As a leading figure of the sixth generation of Chinese directors, Jia Zhangke focuses on recording the great changes since China's reform and opening up with his camera, and pays attention to the relationship between social changes and individuals. Jia Zhangke's films focus on the bottom ecology, love to depict the joys and sorrows of small people, advocating documentary aesthetics, showing a unique image world. Jia Zhangke's early films have typical documentary characteristics, which are also evident in the way of expression of sound, light and color. In terms of sound, dialect dialogue is mainly used. Dialect is more in line with the identity characteristics of the small people at the bottom, and more able to show the current situation of China's population mobility, so dialect dialogue adds to the documentary film; TV, radio and popular music mark the age, radio and television news have real-time, the sense of age is self-evident, popular music also from the point of view of mass entertainment, the film marked the age label; Record the scene noise, mainly including motor vehicles, trains, ships, street pier noise, etc., which also enhanced the scene of the scene. In terms of light, they tend to use natural light, including using active lighting, not avoiding backlighting, and not deliberately adding light. While respecting the authenticity of the shooting scene, they also show the survival status and destiny of the characters. In terms of color, the film is mainly based on gray tone, which is embodied in character modeling and scene tone. The use of sound, light and color is not isolated from each other. Jia zhangke has organically integrated them, showing clearly the underlying world of China in the transition period and shaping a unique documentary style. This paper takes the four feature films XiaoWu, Platform, Unknown Pleasures and StillLife as examples to analyze the documentary characteristics of sound, light and color in Jia Zhangke's films.