【Abstract】Objective To explore the relationship between the expression of MDR1 gene in liver cell and the formation of cholesterol calculus in gallbladder.Methods The mRNA expression level of MDR1 gene in liver cell of the cholesterol calculus group and the normal control group were measured through reverse transcriptionpolymerase chain reaction (RT-PCR)， and microglobulin β2 was used as internal contrast.Results The MDR1 mRNA expression level of the cholesterol calculus group was lower than that of the normal control group(1.30±0.19 vs 2.25±0.28, P＜0.01). Conclusion The formation of cholesterol calculus in gallbladder is related to the reducd expression level of MDR1 gene in liver cell.