Abstract: To investigate the growth and adaptation of Heptacodium miconioides under different light conditions,two-year-old H.miconioides seedlings were used as materials under three light intensities（full light,60% shade and 90% shade）,and the photosynthetic characteristics and non-structural carbohydrate（NSC）content of H.miconioides were measured.The results showed that:（1）The diurnal changes of net photosynthetic rate（P_n）of H.miconioides seedlings under three light intensities showed “single-peak” curves.The daily mean values of P_nunder three light intensities ranked as full light＞60% shade＞90% shade.The daily mean values of water use efficiency(W_UE)under 90% shade treatment was significantly lower than those under full light and60%shade treatments;（2）Compared with full light,the light compensation point(L_CP)and dark respiration rate（R_d）of H.miconioides seedlings under 60%shade decreased significantly,while the light saturation point(L_SP),maximum net photosynthetic rate(P_nmax),maximum carboxylation rate(V_cmax),maximum electron transport rate(J_max),and triose phosphate utilization rate(T_PU)had no significant difference respectively.As shading degree increased,the L_SP,P_nmax,L_CP,R_d,V_cmax,J_maxand T_PUof H.miconioides seedlings under 90% shade were significantly lower than those under full light and 60%shade treatments.（3）The contents of starch,soluble sugar and NSC in leaves of H.miconioides seedlings were highest under 60% shade treatment,and decreased significantly under 90% shade treatment.The NSC content of H.miconioides seedlings was significantly positively correlated with P_n,V_cmax,J_maxand T_PUrespectively.Therefore,H.miconioides had ability of photopholic and shade-tolerant at the seedling stage,and plants could adjust the photosynthetic characteristics of leaves by reducing L_CPand R_d,and maintained a high NSC content under moderate shading conditions,thereby to improve the utilization rate of weak light and carbon assimilation ability,however,excessive shading was not conducive to the growth of H.miconioides seedlings.