To explore effects of Paeoniflorin on Aconitine transport behavior in CacCo-2 cell monolayer model. Methods: Bi-direction transport behaviors of Aconitine and effects of concentrations, incubation time on Aconitine transport behavior were studied on Caco-2 cell. The concentration of Aconitine was analyzed on a reverse-phase HPLC column, Papp value and total transport amount were calculated. The effect of P-gp inhibitor on Aconitine transport behavior was investigated as well. Results: The transport volume of Aconitine was correlated positively with the incubation time and drug concentration. There were no significant differences in the Papp value at the selected concentrations. Bi-directional transport studies on Aconitine showed that the ratio of permeability in the Basolateral to Apical direction is about 1.5 times that of the Apical to Basolateral direction. The Papp value of Aconitine was above 1×10-6 cm·s-1. The transport amount of Aconitine was significantly increased in the presence of Verapamil. The transport amount of Aconitine was significantly reduced, when the ratio of Aconitine and Paeoniflorin compatibility was 1∶60. Conclusion:The results suggested that Aconitine could be easily absorbed on the Caco-2 monolayer model by a passive transportation. However, efflux protein may also play an important role in the transport process. When the compatibility of Paeoniflorin and Aconitine reached a certain percentage, intestinal absorption of Aconitine would be reduced remarkably.