Abstract: The complex ~(99)Tc~mN-HL91 is synthesized through ligand exchange reaction. The ~(2+) (intermediate) is prepared with succinic dihydrazide (SDH) as a donor of nitride nitrogen atom (N~(3-)) in the presence of stannous chloride dihydrate a reductant at room temperature. Then HL91 is added to the \~(2+) intermediate and react at 100 ℃. The labeling efficiency of the product is over 90% measured by thin layer chromatography(TLC). The lg P of ~(99)Tc~mN-HL91(-1.026±0.019) indicates it is a hydrophilic complex. It is stable over 6 h at room temperature. The biodistribution results in mice indicate that it has quick blood and liver cleanness than ~(99)Tc-HL91. It differs from ~(99)Tc~m-HL91 in the hypoxic selectivity and biologic metabolism. ~(99)Tc~mN-HL91 has no significant uptake in hypoxia tumors in tumor-bearing mice.