Abstract: 【Objective】This study examined the effect of stump water storage on the photosynthesis and transpiration characteristics of Phyllostachys heterocycla cv. Pubescens(moso bamboo)under a simulated drought environment, and the relationships between net photosynthetic rate, transpiration rate and environmental factors. The objective of the study was to provide a theoretical reference for water-saving irrigation in moso bamboo forest. 【Method】The experiment included three different irrigation treatments:CK(0 stumps with water storage), T1(12 stumps with water storage)and T2(18 stumps with water storage), the physiological parameters of photosynthesis and transpiration of 2-year-old moso bamboo and the main environmental factors of stands were measured. 【Result】 ① The trends of net photosynthetic(P_n)and transpiration rate(T_r)of moso bamboo in the day were consistent. Both could be presented as unimodal curves and the “photosynthetic noon break” phenomenon could not be detected. The net photosynthetic and transpiration rates of moso bamboo increased with an increase in the number of water storage stumps. ② For the three treatments, the water-use efficiency(E_WUE)of moso bamboo was shown as a bimodal curve. With an increase in the number of water storage stumps, there was a decrease in the water-use efficiency of moso bamboo. ③ Environmental factors played different roles in moso bamboo net photosynthetic rate with different treatments. For example, in CK, the most important direct environmental factor influencing net photosynthesis rate was air relative humidity(φ), whereas for T1 and T2, it was photosynthetically active radiation(R_PAR). However, for transpiration rate, the environmental factor with the largest influence in all treatments was atmospheric CO₂ concentration(C_a). ④ For all treatments, the variable having the largest influence on net photosynthetic rate and transpiration rate was R_PAR. For T1 and T2 treatments, the main variables limiting net photosynthetic and transpiration rates were air temperature(t_a)and φ, whereas for the CK treatment, they were φ and C_a. 【Conclusion】The net photosynthetic rate and transpiration rate of moso bamboo was positively correlated with the number of stumps with water storage, whereas the water-use efficiency of moso bamboo was negatively correlated with the number of stumps with water storage. An increase in the number of stumps with water storage significantly enhanced the photosynthetic and transpiration capacity of moso bamboo, and also enhanced the accumulation of photosynthetic products in moso bamboo. Moreover, the number of stumps with water storage modified the influence of environmental factors on the net photosynthetic rate and transpiration rate of moso bamboo under different treatments.