Abstract: Acer catalpifolium is a unique species and wild endangered one in China. Currently, no research has addressed its endangered status from the perspective of photosynthetic characters. The photosynthesis characteristics and growth rate of A. catalpifolium seedlings from four provenances (Dujiangyan, Dayi, Emeishan and Leibo) under two shading conditions (50% and 80% of full shade) were examined to explore the light response mechanism. The results showed that the net photosynthetic rate (P_n), stomatal conductance (g_s), transpiration rate (T_r) and water use efficiency (WUE) of A. catalpifolium seedlings from four provenances sharply decreased with the decreases of light intensity. When the light intensity was reduced, the light compensation point (LCP) and light saturation point (LSP) of A. catalpifolium seedlings from Dujiangyan and Emei-shan were all decreased, while those of the seedlings from Dayi increased, and those of the seedlings from Leibo showed no significant changes. Net photosynthetic rate and water use efficiency were positively correlated with plant height and crown growth. The effects of different light intensities on photosynthetic characteristics and growth rate of A. catalpifolium were significantly different. Low light availability under canopy might be the limiting factor for natural regeneration of A. catalpifolium populations from Dayi. Compared with other provenances, A. catalpifolium seedlings from Leibo were more shade requiring. A. catalpifolium had better light adaptability and growth performance from Dujiangyan and Emeishan, which could be used as high-quality source for transplant protection.