Abstract: Parrotia subaequalis, an endangered species endemic to eastern China, is in the firstclass national list of key conservative plant. We investigated the adaptation of its seedlings to different light availabilities created by different layers of black nylon net over the nursery site. The treatment of light availabilities included three levels, l00 %, 50 % and 5 % of natural illumination, we measured photosynthesisrelated parameters and growth characteristics of seedling leaves under these three light environments. Results showed that the maximal rate of photosynthesis, light compensation point and light saturation point of leaves decreased under the low light environment in the summer growing season, which implicated that seedlings of P.subaequalis could adapt to low light intensity to a certain extent. Although the leaves have the highest Pn,max under the full daylight, their nonphotochemical quenching coefficient were significantly higher than that in 5 % and 50 % natural illumination, which showed the leaves of seedlings could not use high intensity light and dissipated part of absorbed light energy in the form of heat. Saplings in 50 % natural illumination had the greater adaptive response than that in 5 % and 100 % natural illumination, which had significantly higher specific leaf area and number of leaves per individual. Chlorophyll content of saplings in 5 % natural illumination was significantly higher than that in 50 % and 100 % natural illumination, which may be one of the most important strategies to adapt to very low light conditions. Performances in photosynthetic physiology and morphological characteristics of saplings’ leaves in the low light environment demonstrated their high ability of darkadaptation. However, as one typical lightdemanding tree species, there is certain inhibition in growth and biomass accumulation of saplings under low light environment in the later stage, which may contribute to the limitation of population regeneration. Improving light conditions by human intervention, such as selective removal and cutting of shrubs may contribute to individual establishment and population regeneration of P.subaequalis.