Abstract: The technique of milking medical 90Y from 90Sr.cow by electrodeposition is studied. using 0.1 mol/L pH 2.5 (NH4)2SO4 as electrodeposition solution, platinum as anode, and platinum or stainless steel as cathode, the current density of cathode is controlled at 0.5A/cm2. After electrodeposition for 50 minutes ，more than 95% 90Y can be deposited quantitatively on the cathode. Though two-step electrodepositon, the 90Y/90Sr separation coefficient and elution recovery of 90Y are more than 8 ×105 and 70% respectively. The 90Y deposited on platinum cathode can be eluted by 200~400μL of 0.1~0.5mol/L hot HNO3, which is used to label monoclonal antibodies and peptide-receptor. The stainless steel cathode with deposited 90Y can be prepared to radioactive stent or medical patch, the former is used for the prevention of vascular restenosis, the later for the therapy of inflammation, the daily leaching efficiency of which are less than 1% and 0.1% respectively.90Sr remained in the deposition solution will generate new 90Y, so from which 90Y can be milked again