Abstract: The "ceiling method" was used to simulate throughfall exclusion for the Phyllostachys edulis forest. The Li−6400 portable photosynthesis meter was used to measure in situ seasonal changes in light response of P. edulis at different ages under different drought treatments. The dynamic response of P. edulis photosynthetic capacity to drought at different ages was analyzed through the correlation between photosynthetic physiological indicators. The results showed that when the photosynthetically active radiation (PAR) was less than 200μmol/（m²·s）, the net photosynthetic rate (P_n) for leaves of different ages of P. edulis increases rapidly with the increase of PAR under different drought treatments. When PAR> 200μmol/（m²·s）, the P_n gradually increases to the highest and remains stable. There were significant differences (P<0.05) in the photosynthetic parameters of P. edulis at different ages among seasons, ages, and drought treatments. Under drought conditions, the P_{n max} and AQY of 5 years old P. edulis (D_5a) were higher than those of the control P. edulis (CK_5a) in all seasons except autumn. The light compensation point (LCP) in summer and light saturation point (LSP) in winter were significantly lower than those of the control P. edulis. Under drought conditions, the LSP of 3 years old P. edulis (D_3a) in summer and autumn was higher than that of the control (CK_3a), while the P_{n max}, R_d in autumn and winter, and LCP in winter were all lower than those of the control. Under drought conditions, the P_{n max} of one year old P. edulis (D_1a) in summer and autumn was significantly higher than that of the control P. edulis (CK_1a), while the AQY in spring and winter and LCP and R_d in autumn were lower than those of the control. Drought treatment significantly reshaped the stomatal regulation and water-use strategy of P. edulis, showing significant seasonal and age differences. It is evident that the response of P. edulis to drought stress exhibits significant age-related differences and seasonal dynamics. The 5 years old bamboo demonstrates the strongest drought resistance by optimizing stomatal regulation and improving water-use efficiency. The 3 years old P. edulis adopts a seasonal adaptation strategy. In contrast, 1 year old bamboo is constrained by non-stomatal factors, resulting in relatively weak drought resistance.