Abstract: OBJECTIVE To develop an HPLC method for determination of main components in prepared rhubarb decoction and investigate its effects on rats with noxious heat blood stasis syndrome. METHODS The analysis was performed on a Hypersil GOLD C₁₈ column with the mobile phase of 0.1% phosphoric acid solution(A)-acetonitrile(B). The detection wavelength was set at 254 nm and the column temperature was 30 ℃. The method was validated and the samples were determined under this condition. The abdominal aortic blood of rats with noxious heat blood stasis syndrome was collected and tested to obtain the hemorheological parameters. Also， the TXB₂ and 6-keto-PGF_1α levels in rats plasma were measured. RESULTS The developed HPLC method showed good linearity within certain concentration ranges. And the precision， repeatability， stability and recovery all met the requirements. Compared with rats in model group， the whole blood viscosity at four shear rates（P<0.05）， plasma viscosity（P<0.01） and the level of plasma fibrinogen content（P<0.01） in the high dose group were significantly decreased after doing， and the TT（P<0.01） and PT（P<0.01） values were significantly prolonged. Furthermore， the levels of TXB₂（decreased， P<0.05） and 6-keto-PGF1α（increased，P<0.05）were significantly changed， and their ratio was corrected to be normal. CONCLUSION The method was simple， accurate and reliable，which could be used for quality control of prepared rhubarb decoction. Prepared rhubarb could improve vascular endothelial function by modifying blood rheology， promoting the secretion of PGI₂， reducing the generation of TXA₂ and recovering the balance of TXB₂/6-keto-PGF_1α.