Tin-117m(t1/2 14d; γ 159keV, 86%) is an ideal tracer for studying biological behavior of tin compounds as well as for developing clinically-useful radio-pharmaceuticals. It had been reported that Sn-117m[4+] DTPA has unexpectedly high bone uptake and bone-to-blood ratio, and is potentially useful as an agent for skeletal scintigraphy and radiotherapy of bone tumors. In this work, HEDTMP [N-(2-hydroxyethyl) ethlenediamine-l,l,2-tri (methylene phosphonic acid)] was synthesized. Let it form complex with 117mSn. The formation conditions, stability and distribution coefficient between oil and water of the complex were investigated. Tin-117m (t1 / 2 14d; γ 159keV, 86%) is an ideal tracer for studying biological behavior of tin compounds as well as for developing clinically-useful radio-pharmaceuticals. It had been reported that Sn-117m [4+] DTPA has unexpectedly high bone uptake and bone-to-blood ratio, and is potentially useful as an agent for skeletal scintigraphy and radiotherapy of bone tumors. In this work, HEDTMP [N- (2-hydroxyethyl) ethlenediamine- Let it form complex with 117mSn. The formation conditions, stability and distribution coefficient between oil and water of the complex were investigated.