Abstract: Ardisia crenata Sims has a broad potential commercial application with both ornamental and medicinal value. A. crenata Sims were planted in pots which were placed in understory, greenhouse, and open-air, morphological structure, photosynthetic and chlorophyll fluorescence characteristics were measured and analyzed to provide reference for cultivation and promotion of A. crenata Sims. The results showed that: (1) The plant height, first branch height, longest branch length, canopy width, branch diameter, leaf width, stem diameter at ground level, leaf number on the longest branch, and branch number of A. crenata Sims in the understory were significantly higher than those in the greenhouse and open-air, while the leaf length was significantly higher than that in the open-air and slightly higher than that in the greenhouse, the leaf thickness was significantly lower than that in the open-air and slightly lower than that in the greenhouse; (2) The photosynthetically active radiation (PAR) and intercellular CO₂ concentration (Ci) of A. crenata Sims in the understory were significantly lower than those in the greenhouse and open-air, while the net photosynthetic rate (Pn) and transpiration rate (Tr) were significantly higher than those in the greenhouse and open-air. The canopy stomatal conductance (Gs) were slightly lower than those in the greenhouse and significantly lower than those in the open-air; (3) The initial fluorescence (Fo) of A. crenata Sims in the understory was significantly lower than those in the greenhouse and open-air, while the maximum fluorescence (Fm) was significantly higher than those in the greenhouse and open-air. No significant differences in the maximum PSII light energy conversion efficiency (Fv/Fm), non-photochemical quenching (qN) and actual photochemical efficiency of PSII (ΦPSII) of A. crenata Sims among understory, greenhouse and open-air treatments, while the photochemical quenching (qP) in the understory was slightly lower than that in the greenhouse and significantly lower than that in the open-air. The optimal development of morphology and structure and the highest photosynthetic utilization efficiency of A. crenata Sims were detected in the understory, therefore, understory is optimal for A. crenata Sims.