The aim of this study is to reveal the effects of the UO₂²⁺ complexes and P. Fluorescens on adsorption and reduction of uranium under the condition of different carbon and nitrogen sources of CZA(Czapek-Dox medium). On the basis of the formulation of CZA, sugar was replaced by glucose and sodium nitrate was replaced by ammonium chloride,and then the Visual MINTEQ was used to analyze the UO₂²⁺ complexes. The results show that different types of carbon and nitrogen sources have no effects on the growth of P. Fluorescens. There exist different types of complexes of UO₂²⁺ when uranium concentration is changed. UO₂²⁺ mainly occurs as UO₂PO₄^_ when uranium concentration is 10 mg/L, and as UO₂(SO₄)₂²⁺ when uranium concentration is 50 to 200 mg/L in CZA medium. UO₂²⁺ exists as UO₂HPO₄(aq) when dextrose serves as carbon source, and as UO₂Cl₂(aq) when ammonium chloride serves as nitrogen source. The tolerance concentration of uranium for fluorescent pseudomonas is higher than 100 mg/L in general, and loses its activity at 200 mg/L. Compared with live and inactivation of P. Fluorescens, carbon and nitrogen sources have little effects on the adsorption and reduction of uranium. The adsorptions range from 84.02% to 92.59% and 3.32% to 10.94%, and the reduction rates range from 3.32% to 10.94% for living P. Fluorescens. The adsorption rates are 24.33%~39.05% and the reduction rates are 37.50%~44.58% for inactivated P. Fluorescens. The reduction rate of uranium is 53.12% when glucose is used as carbon source. The results indicate that inactive bacteria and reductive glucose as carbon source synergistically reduce uranium. However, no obviously synergistically effects exist for P. Fluorescens under living conditions.