Eight-year-old Castanea henryi cv. Huali 4 (Fagaceae) trees were studied in order to explore the relationship between tree shape and light use by C. henryi, and provide scientific advice on the cultivation and management of this species. An illuminometer, a chlorophyll meter and a portable photosynthesis system were used to measure relative light intensity in different tiers of the canopy, and the diurnal course of ecophysiological and photosynthetic parameters were measured to ascertain the effects of different tree forms on the photosynthetic performance and yield of C. henryi. The results showed that: 1) the relative light intensities of the three tree shapes (open center, small and sparse canopy, and natural roundhead) created by specific training and pruning regimes were all significantly higher than the control (trees not trained or pruned, but left to grow naturally) for all the canopy positions. Relative light intensity followed the same trend, regardless of canopy position (open center shape > small and sparse canopy > natural roundhead shape). The relative light intensity in the outer layer of the open center shape was highest (93.89%), This was 10.34% higher than the value for the small and sparse canopy shapes, 23.29% higher than in the natural roundhead shape, and 41.08% higher than the control. These results indicated that C. henryi received more light when it had an open center shape. Diurnally, the net photosynthetic rate (P_n) for C. henryi leaves taken from different shaped trees had two peaks at 10:00 and 14:00. The P_n for leaves on the open center shaped trees (9.97 μmol m^-2s^-1) was higher than the values for the other two shapes and the control. 2) Some photosynthetic parameters differed significantly among the tree shapes. The maximum P_n and the light saturation point in trees with the open center shape were higher than the values recorded for the other tree shapes. However, the CO₂ compensation point and dark respiration rate for leaves on the open center shaped trees were lower than the values for the other two tree shapes and the control. Additionally, the carboxylation efficiency of the open center shaped trees was significantly higher than it was for the other shapes, all of which indicated that the photosynthetic performance of the open center shape trees was better than the other shapes. 3) The chlorophyll fluorescence parameter results showed that maximum fluorescence (F_m), PSⅡ maximal efficiency (F_v/F_m), PSⅡ potential efficiency (F_v/F_o), and the electron transport rate (ETR) for each of the three tree shapes significantly improved compared to the control. The ETR in the open center shaped trees was higher than the ETR values for the other two tree shapes and the control. 4) There were significant differences (P ≤ 0.01) in P_n, transpiration rate, F_v/F_o, ETR, chlorophyll content, and yield per plant, and the correlation index between P_n and yield per plant was highest (r=0.835). Thus, manipulating tree shape by training and pruning can significantly improve the ventilation and light conditions in the inner layer of a tree, improve the utilization ratio of light energy, and increase yield. Based on our results, C. henryi trees with an open center shape are superior in light energy use to the ones with small and sparse canopies and natural roundhead shapes. Therefore training and pruning C. henryi to have an open center shape will improve yields.