Objective: To study the pharmacokinetic and bioavailability of 23-acetyl alisol B from Rhizoma Alismatis by different administration.Method: 23-acetyl alisol B was given by oral administration and intravenous injection to rats respectively and blood sample were withdrawn at different time.23-acetyl alisol B in plasma samples were determined by HPLC-UV method.The mobile phase consisted of acetonitrile and water（80∶20）.The detection wavelength was at 210 nm;the flow rate was 1.0 mL·min-1.The model of pharmacokinetic was built by the drug-time curve and the parameters and absolute bioavailability were calculated.Result: The main pharmacokinetic parameters of 23-acetyl alisol B in rats were Tmax =（122.15 ± 15.23） min

Cmax =（9.89 ± 0.87） mg·L-1

t1/2 =（58.72 ± 6.23） min

AUC0-t =（1 854.970 ± 142.31） mg.min·L-1

AUC0-∞ =（1 875.81 ±144.27） mg.min·L-1

CL /F =（2.89 ± 0.13） mL·min-1 for oral administration and are Tmax =（10.04 ± 0.78）min

Cmax =（42.59 ± 3.47） mg·L-1

t1/2 =（32.05 ± 2.53） min

AUC0-t =（2 810.08 ± 178.70） mg.min·L-1

AUC0-∞ =（2 812.41 ± 224.63） mg.min·L-1

CL /F =（1.74 ± 0.54） mL.min-1 for intravenous injection.Mean bioavailability（F） was 44.46%.Conclustion: The absorption of 23-acetyl alisol B in rats is slow but complete comparing with the quick elimination.It implied that 23-acetyl alisol B has good pharmacokinetic characteristics

and can be easy to develop into a clinical drug which can be convenient to use.