OBJECTIVE To establish a method for determining the protein binding rates of apigenin in rat plasma, human plasma.bovine serum albumin (BSA).and to calculate the correlate related parameters of apigenin in different matrix. METHODS The concentrations of apigenin in different matrix were assayed by high performance liquid chromatography (HPl.C). The protein binding rates of apigenin in different matrix were determined by equilibrium dialysis method. RESULTS The protein binding rates of apigenin with rat plasma,human plasma and BSA were (99. 4 ± 3.8) %. (99. 6 ± 5. 6) %, (99. 5 ± 4. 5) %, respectively, when high concentration of apigenin was used;they were (96. 3 ± 7. 2)%, (97. 9 + 10. 5)%. (97. 8 ± 9. 7)% .respectively, when medium concentration of apigenin was used;and they were (98. 7 ± 8. 6)%, (99. 6 + 9. 4)%, (99. 1 +8.0)%, respectively,when low concentration of apigenin was used CONCLUSION The method was validated to be rapid.and reliable. The protein binding rates of apigenin with rat plasma, human plasma and BSA were very high. Moreover, the plasma protein binding rates were dose-independent.