A portable Li-6400 XT photosynthesis measuring system (LI-COR Biosciences, Lincoln, NE, USA) was used to explore how Torreya jackii, an endangered species endemic to China, adapts to the environment and to illustrate and determine various photosynthetic characteristics of T. jackii in three natural habitats with different light conditions, specifically gap, edge and understory habitats. Also, the physiological mechanisms that have resulted in the endangered status of this species were explored to provide baseline reference data in support of off-site conservation and population rejuvenation of T. jackii. The results for T. jackii growing in forest gap and edge habitats show that when the diurnal variation in the photosynthetic rates in the summer is graphed, typical curves with double peaks appear; in addition, photosynthetic rates in the other seasons show curves with a single peak as do photosynthetic rates in understory habitat based on data in all four seasons. The net photosynthetic rate (P_nmax), light saturation point (LSP), apparent quantum yield (AQY), maximum rate of carboxylation (V_cmax), maximum rate of electron transport (J_max), and triose phosphate use rate (TPU) were highest in summer in all habitats; this indicates the photosynthetic capacity of T. jackii is significantly higher in summer than in other seasons. The graphs indicate a midday depression of photosynthesis occurs in summer in gap and edge habitats when the dark respiration rate (R_d) and light compensation point (LCP) are also higher. As a result, the daily mean values of P_n in gap habitat are significantly lower than in autumn while those of P_n in edge habitat are similar to the daily mean values observed in autumn. In all four seasons the daily mean values of P_n, P_nmax, LSP, V_cmax, J_ma, and TPU in gap habitat are the highest with significant differences between those in gap and understory habitat. These findings indicate that the photosynthetic characteristics of T. jackii are typical for a plant growing in sunny habitats, meaning T. jackii grows more vigorously in gap habitat with adequate light. In summer and autumn, the LSP of T. jackii is lower than those of other plants typically associated with its habitats, while the LCP is higher than those of the associated plants, which indicates that T. jackii has a narrow ecological range of adaptability to light conditions. The P_n of T. jackii is lower than those of the associated plants in the community, indicating that T. jackii is at a disadvantage during interspecific competition with its poor ability to adapt photosynthetically to a wide variety of light conditions; this might be an important factor contributing to the endangered status of T. jackii.