To evaluate the fading of dyed silk scientifically, and to provide valuable lighting design suggestions to museums that exhibit this sort of artifact, light aging tests were designed to study the photodegradation effects of different lighting sources. The light fastness of silk dyed with natural plant yellow dyes (berberine and pagoda tree buds) was tested under three commonly used museum lighting sources (LED lamp, fluorescent lamp and halogen lamp). Chromatic difference analysis and high performance liquid chromatography (HPLC) were used to analyze the silk samples after light exposure. The results show that the halogen lamp cause the least fading of the dyed yellow silk samples, i.e., lower than the common LED lamp and the fluorescent lamp. The main components of the dyes before and after light aging were analyzed by HPLC, and degradation mechanisms are proposed.