Abstract: To study the effect of chelating agent on absorption, accumulation and transport characteristics of sunflower under U contaminated soil is of certain significance. The concentration of U in soil was 150 mg/kg, added EDDS、CA and OA with the concentration of 2.5, 5.0 and 7.5 mmol/kg, and the effects on sunflower growth, U absorption and activation property of U in soil were investigated. The results showed that different treatments of chelating agents decreased the biomass of sunflower, and the decreasing degree reached the largest under high concentration of chelating agent; the addition of CA could increase available U concentration more significantly than EDDS and OA, at the same time, the enrichment coefficient and transport ability of sunflower were also enhanced; the maximum value of the transport coefficient was 0.063 when CA concentration was 7.5 mmol/kg, which was 1.42 times of that of CK. Under this concentration, U content of roots and overground part was 178.95 and 11.27 mg/kg, respectively, which was 2.21 and 3.45 times of that of CK. The maximum activating U content was 104.59 mg/kg, which was 1.63 times of that of CK, U oncentration in roots was higher than that in overground part under all treatments. Therefore, proper addition of chelating agent could increase available U concentration in soil effectively, and promote the absorption and transport of plant.