Abstract: In recent years, ~(90)Y has been considered as one of the best radionuclides for tumor radioimmunotherapy when chelated to tumor-associated antibodies. This evaluation is based on the superior properties of this radionuclide (suitable half-life, pure β-ray emitter of intermediate energy, stable daughter, and suitable chemical properties) and because it is available as a radionuclide generator product by decay of its 28a parent ~(90)Sr.In this paper experimental conditions of the ~(90)Sr-~(90)Y generator are described. The elution efficiency of ~(90)Sr-~(90)Y generator reaches 98%. One of the most important problems is the ~(90)Sr contamination breakthrough from the generator. The level of ~(90)Sr contamination must be controlled to reach the clinical standard. The cation exchange resin 732(100—150 mesh)was successfully used for the separation of ~(90)Y from ~(90)Sr. Our method provides a ~(90)Y-HAc solution which is very simple and safe for administration to the patients. ~(90)y was separated from ~(90)St almost completely, the level of the ~(90)Sr contamination per 740MBq ~(90)Y product was only 0.74kBq. However the toxicity of ~(90)Sr is extremely high, the human life-time permissible dose is 74kBq,then 740MBq of ~(90)Y is allowed to be administrated to a patient for 50—100 times.