Because traditional dwellings are basically built by the villagers, and the light environment design is rarely considered, the indoor lighting effect of the building is poor. In order to improve the light environment of traditional dwellings, a light environment experiment was carried out on a representative Miao dwelling in Huangtu Village, Danzhai County, Southeast Guizhou. The light environment was studied in combination with the spatial characteristics of the dwellings. The results show that the daylighting performances of the main rooms do not meet the requirements of standard for daylighting design. The size and position of daylighting windows, the form of interior space, and the reflective properties of surface materials all have an impact on the interior light environment. Quantitative analysis of various influential factors was conducted by software simulation. With the premise of minimizing the impact of light environment transformation on the original architectural features and spatial structure, the comprehensive optimization strategies for light environment of traditional dwellings were put forward, such as adjusting the size and quantity of lighting windows, increasing the roof daylighting tiles and daylighting windows under the eaves, paving light color wallpaper, and setting adjustable reflective louver. The results of the study can provide reference for the protective transformation of interior lighting environment of traditional dwellings and the daylighting design of new dwellings.