In order to investigate the effects of Cinnamomum japonicum leaf litter addition on the growth and photosynthetic characteristics of Impatiens balsamina,we conducted a pot experiment.Four litter addition treatments 0(CK),20(L),40(M),80(H) g·pot^-1 were applied.The results showed that the biomass and basal diameter of I.balsamina decreased significantly in M and H treatments,but no obvious change was observed in plant height among all the treatments.Chlorophyll contents of both M and H treatments were significantly inhibited.In treatments M and H,both net photosynthetic rate(P_n) and water use efficiency(WUE) were significantly lower than that of CK,while the three gas exchange parameters,stomatal conductance(G_s),intercellular CO₂ concentration(C_i) and transpiration rate(T_r) were notably higher than those of CK.P_n-PAR curve and P_n-C_i curve showed that under the saturation of light and CO₂ conditions both maximum net photosynthetic rates(P_{n max}) declined with the increasing amount of litter leaf addition,apparent quantum efficiency(AQY),dark respiration rate(R_d),RuBP carboxylation efficiency(CE) and light respiration rate(R_p) decreased as well.After adding C.japonicum leaf litter 36 and 67 days,no obvious effects were witnessed on the growth of I.balsamina,whereas inhibitory effect was observed obviously after 58 days.Overall,C.japonicum leaf litter addition reduced the content of photosynthetic pigments of I.balsamina,inhibited photosynthetic capacity,weakened adaptability to the environment,restraining the growth of the plant ultimately.