Abstract: Dwarf-pruning on Lidongben longan plants at a closed orchard was carried out to study the changes on the photosynthetic characteristics of the plants at fruit maturing stage, the associated environmental factors, and the fruit quality and yield at harvest. After pruning, the light intensity and temperature on the tree crowns increased, and the relative humidity decreased slightly, while the net photosynthetic rate, transpiration rate and stomatal conductance of the leaves significantly increased, but the intercellular CO₂ decreased. The single fruit weight and the soluble solids of the fruits on the upper crowns, as well as the soluble solids of the fruits in the crown interior, increased significantly. However, no significant difference on fruit yield per plant was observed with the pruning.