OBJECTIVE： To study the metabolite and excretion of polydatin （Trans-resveratrol-3-O-glucoside，TRG）  and its metabolites in Beagle dog feces， and provide experimental basis for the new drug development of TRG. METHODS： 4 Beagle dogs were intragastrically administrated TRG 20％ polyethylene glycol 400 solution 50 mg/kg. LC/MS was used to identify the metabolites of TRG in dog feces after 12-24 h of administration， and HPLC was adopted to determine the cumulative excretion rate and excretion speed rate of the major metabolite resveratrol （TR） in feces samples after 0-12， 12-24， 24-36， 36-48， 48-72， 72-96 h of administration. RESULTS： TR and two sulfate conjugates of TR were found in dog feces， and TR was a major metabolite， while TRG was undetermined. The excretion speed rate of TR in dog feces was the rapidest after 12-24 h of administration， reaching 9.65 mg/h. Its cumulative excretion rate was 39.3％， equivalent to 67.2％ of TRG. CONCLUSIONS： After TRG is intragastrically administrated to dogs， TRG was mainly excreted in the form of TR via dog feces.