Abstract: The pharmacokinetic features of andrographolide and dehydroandrographolide, two effective components of Andrographis paniculata, were investigated in chickens administrated with ultrafine powder of A. paniculata in the paper. The two compounds in chicken plasma were determined simultaneously by HPLC method following oral administration of Andrographis paniculata ultrafine powder at a single dose of 5 g·kg1 B.W., the pharmacokinetic process were evaluated by Pharmacokinetics Program 3P97. The results showed that the plasma concentrationtime data of andrographolide and dehydroandrographolide in chicken plasma could be described by two compartment model with firstorder absorption, with t1/2α of (47.4±3.5 )and (41.9±3.9) min，t1/2β of (104.8±12.8 ) and (143.0±12.8) min，t1/2Ka of (23.2±2.6 )and (9.77±1.22) min，AUC of (329.3±28.8) and (329.1±25.5) (μg·mL1)·min，tmax of (51.5±3.5) and (37.2±2.8) min，Cmax of (1.60±0.32 )and (1.44±0.09) μg·mL1，MRT of (175.2±15.9) and (219±18 )min for them respectively. The pharmacokinetic rule of the ultrafine powder could be reflected by kinetic process of the two constituents in chickens, between which significant or extremely significant difference exited in absorbtion and elimination stage, and the study could provide references for the clinical application of the powder preparation of Andrographis paniculata, also do for the pharmacokinetic study on multiconstituents from Chinese traditional medicine.