Abstract: A new organogermanium sesquisulfide is synthesized and identified by IR spectrum and elemental analysis method.The new compound is labeled by 99Tc m and the labeling yield is 84.2% under the best condition (ligand, 0.5 mg; SnCl 2, 0.1 mg; pH≈8.0; reaction temperature, 20 ℃; reaction time, 20 min). The biodistribution experiments in mice of the 99Tc m labeled compound show that it is mainly concentrated in lung,next in liver.When the mass concentration of the labeled compound is 50 μg/mL,its antitumor activity against KB,HCT and Bel cells in vitro is 69.0%,76.9% and 44.7%,respectively.