Abstract: The spectrophotometric determination of uranium in high level liquid waste and its separation process with arsenazo Ⅲ are studied. In the presence of tartaric acid (pH=1.5), stripping and determination of uranium are completed. When the presence of rare earth elements and the concentration of uranium is lower than 0.6 mg/L in aqueous solution, uranium must be separated from the solution and then is determined. The detection limit of uranium is 0.02 mg/L, the precision of the method is 3 %, the recovery of added standard sample is 97 %～105 %,respectively.