This paper aims to investigate the portal-vein absorption kinetics of berberine in rat, and the influence of P-gp inhibitors such as verapamil and borneol, to its absorption ability. In the paper, a validated UHPLC method was established to determine the berberine in plasma, and the portal-vein absorption model was applied to conduct the pharmacokinetic study. Animals were divided into four groups as follow: group berberine group (BG); group verapamil + berberine group (VBG); group borneol + berberine group (BBG) and group long-term use of borneol + berberine group (LBBG). Plasma samples were obtained at regular time intervals after administration and separated on Agilent 1290 Infinity UHPLC instrument. The method showed good linearity (r = 0.9988) over wide dynamic ranges (4.08-163.20 ng/mL). Variations within- and between-batch never exceeded 7.58 and 2.21 %, respectively. The extraction recovery rates ranged from 85.34 to 111.62 %. We discovered that the AUC of four group exhibited no significant differences (P > 0.05), and co-administration of berberine with borneol of group BBG and group LBBG in advance could both reduce the T max and C max as compared to group BG (P < 0.05), while co-administration of verapamil seems to have had little influence to berberine's absorption ability.