Along with the development of the nuclear industry,heavy metal uranium emissions and spread was increasing,and it will bring potential harm to human health.In this study,wheat seedlings (Triticum aestivum L.var.Xikemai No.3) were cultivated with hydroponic culture system,and were respectively treated with nutrient solution containing 0,5,20,50,100 mg·L^-1 U[UO₂(NO₃)₂·6H₂O] after five-leaf stage.Uptake and distribution of U in the up-ground parts and down-ground parts of wheat,the chlorophyll fluorescence characteristics and photosystem activity were investigated after 7 days of the U treatment.The results showed that:(1)Wheat can absorb the U,but both of the bio-enrichment coefficients and the transfer factors were very low,and the U was mainly accumulated in the roots.(2)The chlorophyll b content of leaves was significantly declined under the U stress,while the chlorophyll a content slightly decreased,and the carotenoid content maintained stable.After the U treatment,Both of photosystem Ⅱ (PSⅡ) and photosystem Ⅰ(PSⅠ) activity were subject to different affects,among them,the PSⅡ reaction center activity was inhibited,but the electron transport activity of donor and receptor side in PSⅡ,as well as PSⅠactivity were promoted.(3)Low concentration of U affected the balance between PSⅡ and PSⅠ of wheat leaves,and there was stronger promoting on the PSⅠ activity than on the PSⅡ activity.