Abstract: Pot experiment was conducted in greenhouse in Wangcheng Village, Enshi County of Hubei, China to study photosynthetic character and variation of assimilate accumulation of flue-cured tobacco Yunyan87 under different soil Se application rates ( 0, 1, 2.5, 5, 10 and 15 mg/kg). The results showed that suitable Se rate could reduce the decline rate of net photosynthetic rate (Pn) and photosynthetic pigment, delay decline of photosynthetic function, and prolong accumulating time of assimilation, but it was opposite under too high concentration. The effects of soil Se-supplement on photosynthetic character and assimilate accumulation of flue-cured tobacco appeared in mature period (about 60 days after transplanting), and the effects gradually increased with the advance of leaf growth stages. Under the conditions of this study, proper soil Se-supplement concentrations were 2.5 and 5 mg/kg.