Abstract:This paper used oriental lily varieties ‘Sorboon’ as experimental material and set lasting 4, 8, 12, 16, 20, 24 days water stress and rewater 4 days after 24 days water stress.Chlorophyll content, photosynthetic characteristics, protective enzyme, MDA were tested and root system development situation was observed. Pollen fertility was also researched during water stress, rewater and flowering periods. The effects of root, leaf physiology function and pollen fertility under water stress situation were also discussed. The results show that: (1) compare with normal conditions, after 4 days water stress, lily begin to be effected. 4-8 days, stomatal limitation is the major factor to effect lily. 8-12 days, fluorescent chlorophyll index of leaf decreased dramatically. The limitation of photosynthetic had transferred from stomatal factor to non stomatal factor. After 12 days water stress, membrane began to be oxidized and MDA content increased. After 16 days, protective enzyme system was effected and antioxidant enzyme activity decreased gradually. At the end of water stress, index of fluorescent chlorophyll recovered slightly. (2) After 4 days rewater treatment, all index of photosynthesis recovered, but lower than the level of normal. The results show that chloroplast was destroyed under the 24 days water stress treatment. (3) Compare with the control, root system became short and thick firstly, then less, dry and shrink at last with water stress aggravate. Pollen fertility was no significant change during water stress, rewater and flowering periods. This research discovered: leaf photosynthetic function, protective enzyme and root system suffered damage after lasting 24 days water stress, but pollen fertility was normal under this situation. This study will provide important reference for water saving production and partly reveal the relationship between photosynthetic physiology and water stress of cut flower lily.