【Abstract】ObjectiveTo construct a mrp1 expression vector and investigate its biological characteristics in HepG2 cells in vitro. MethodsThe 6.5 kb multidrug resistanceassociated protein （MRP) cDNA obtained from plasmid pGEM-mrp1 was cloned into the pCI-neo mammalian expression vector, which was later transferred into human hepatocarcinoma cell line HepG2 by liposome. Then the HepG2 cells resisting G418 were clustered and proliferated, and the mrp1 mRNA and MRP in these HepG2 cells were detected by means of RT-PCR and FCM respectively. ResultsThe mrp1 expression vector was established successfully, and the stable MDR hepatocarcinoma cell line (HepG2/mrp1) was developed as well. The content of the specific fragment of mrp1 mRNA was (56.8±6.37)% and MRP was 7.89 in the HepG2/mrp1 cells, the corresponding value in HepG2 cells was (9.67±3.26)% and 0.79 respectively. The difference was statistically significant (P＜0.05). ConclusionIt is practicable to establish MDR hepatocarcinoma cell line by transferring mrp1 cDNA into HepG2 cells, which is useful in the research of MDR mechanism.