Abstract: To investigate the light adaptability and the strength of carbon fixation and oxygen release of different ornamental bamboos in summer and their influencing factors and select bamboo species that can enhance the carbon sink benefits in the context of global warming,by measuring the diurnal variation parameters and light response curves of photosynthesis in five local ornamental bamboo species in Fujian Province,including Acidosasa edulis,Bambusa ventricosa,Semiarundinaria densiflora,Sinobambusa tootsik f.luteoloalbostriata,and Bambusa vulgaris f.vittata,the interaction between factors affecting photosynthesis and their effects on carbon sequestration and oxygen release were analyzed.The results showed that the light response model most suitable for 5 species of ornamental bamboo was the right-angled hyperbolic correction model.The correlation between carbon fixation of bamboo species and net photosynthetic rate reached a very significant level,and the factors affecting the diurnal change of net photosynthetic rate of the five ornamental bamboo species were different.The net photosynthetic rate of Acidosasa edulis was highly significantly correlated with the transpiration rate and stomatal conductance,Bambusa ventricosa was highly significantly correlated with the transpiration rate,and Sinobambusa tootsik f.luteoloalbostriata was significantly correlated with the water use efficiency.Semiarundinaria densiflora and Bambusa vulgaris f.vittata was highly significantly correlated with the stomatal conductance.The net photosynthetic rate,stomatal conductance,and daily average intercellular CO₂ concentration of Bambusa vulgaris f.vittata,Semiarundinaria densiflora,and Bambusa ventricosa were relatively high,and their carbon sequestration and oxygen release were also relatively high.In summary,the light adaptability and carbon sequestration ability of different ornamental bamboo are different,and the ecological adaptability of Bambusa vulgaris f.vittata is better under high temperature in summer.