OBJECTIVE：To s tudy the intestinal absorption differences of 6 kinds of active constituents of Polygonum orientale （kaempferol，isokaempferol，vitexin，protocatechuic acid ，kaempferol-3-O-β-D-glucoside and quercetin ）in normal and myocardial ischemia（MI）model rats. METHODS ：UPLC-MS/MS method was adopted to determine the contents of 6 active components in the intestinal circulatory perfusion fluid. Totally male SD 80 rats were divided into normal group and model group ，with 40 rats in each group. Model group was given isoproterenol hydrochloride （50 mg/kg） subcutaneously to induce MI model；normal group was given constant volume of normalsaline， once a day ， for consecutive 2 days. 24 h after successful molding ，normal group and model group received in-situ intestinal circulatory perfusion experiment. The effects of different concentration s of P. orientale extract（5.0，10.0， 20.0 mg/mL），different intestinal segments （duodenum，jejunum，ileum，colon），P-glycoprotein（P-gp）inhibitors（verapamil） and bile on the intestinal absorption of each constituent were explored. RESULTS ：The linear ranges of concentrations of kaempferol， isokaempferol， vitexin， protocatechuic acid ， kaempferol-3-O-β-D-glucoside and quercetin were 3.15-50.40， 3.21-51.31，1.63-52.43，1.60-50.94，1.31-20.97，8.07-129.25 µg/mL（r＞0.999）. The lower limits of quantification were 7.86， 8.45，6.52，4.00，3.28，16.14 ng/mL，respectively. RSDs of precision ，matrix effect and stability tests were all lower than 11％； the accuracy were 85.64％-107.65％，which were in line with the requirements of biological sample quantification analysis. Except for there was no statistical significance in the absorption of kaempferol absorption in duodenum of model group at different concentrations，absorption of other five constituents in duodenum of normal and model rats increased with the increase of the concentration of active constituents ，and absorption of medium- and/or high- concentration active constituents （except quercetin ）in model group was significantly lower than normal group （P＜0.05）. In normal group ，the absorption of kaempferol was more in jejunum，ileum and colon ，isokaempferol was more in ileum ，vitexin and protocatechuic acid were more in jejunum and ileum ， kaempferin-3-O- β-D-glucoside was more in duodenum ，jejunum and colon ，quercetin was more in colon ；in the model group ，the absorption of Polygonum orientale in jejunum and colon was more ，the absorption of isokaempferol in 4 intestinal segments was little different ，vitexin was mainly absorbed in ileum ，protocatechuic acid and kaempferol- 3-O-β-D-glucoside was mainly absorbed in jejunum ，quercetin was mainly absorbed in duodenum and ileum ；in the same intestine ，the absorption of constituents in the model group was less than normal group. After adding verapamil ，absorption of all constituents in the normal group increased ，but the difference was not statistically significant （P＞0.05）；absorption of kaempferol ，isokaempferol，vitexin，protocatechuic acid and kaempferol- 3-O-β-D-glucoside were all increased significantly in model group （P＜0.05），while there was no statistical significance in the increase of quercetin （P＞0.05）. After the bile flowed into the duodenum ，absorption of protocatechuic acid was increased significantly in normal group （P＜0.05）；absorption of other active constituents were increased significantly in model group，except for isokaempferol and quercetin （P＜0.05）. CONCLUSIONS ：Six active constituents of P. orientale were absorbed in the whole intestine of normal and MI model rats ，and the absorption of above constituents may be enhanced more significantly by P-gp inhibitor and bile under pathological condition.