Abstract: In order to investigate the preparation of radioiodinated resveratrol and its biodistribution in mice, resveratrol was labeled with ¹³¹I using lactoperoxidase methods and purified by ethyl acetate. The radiolabeled compound was characterized by polyamide TLC, in which the substratum of V_{trichoromethane}∶ Vacetone∶Vethanol∶VAdam's ale=4∶4∶0.5∶0.4 was used as the developing agent. Biodistribution studies were accomplished on KM mice. At different time after radiopharmaceutical i.v. administration (0.185 MBq ¹³¹Itetrahydropalmatine/mouse), the animals were sacrificed (n=5 animals for each time). Blood and the interested tissues were collected, washed, weighted and counted. The percent injected dose per gram (%ID•g^-1) was calculated for each sample. The labeling yield of ¹³¹Iresveratrol is 69.3% and its RCPs are 95.9%, 92.0%, 90.4%, and 90.1% after 1, 3, 7 and 15 d, respectively. Biodistribution in mice demonstrates that ¹³¹I resveratrol is distributed into broad organs and tissues. However, it reveals higher levels in liver, kidney and intestine than in other tissues. In liver and kidney, the %ID•g^-1are 16.35% and 13.05% at 5 min, respectively. ¹³¹Iresveratrol is metabolized mainly through liver and kidney. Simultaneously, its high distribution is also found in intestine. The %ID•g^-1 of ¹³¹Iresveratrol is 11.70% at 10 min; the activity in thyroid increases with time. Therefore, the ¹³¹Iresveratrol is worthy of further investigation to trace the compound in vivo and ex vivo.