〔Abstract〕 Objective To investigate the mechanism of miR-21 in anti-tuberculosis drug-induced hepatocyte injury. Methods Human normal hepatocytes(HL-7702) were cultured to construct the hepatic injury cell model at the optimum concentration of three drugs. Cells were divided into six groups: control group, drug group, drug+miR-21 inhibitor group, inhibitor negative control group, drug+miR-21 mimics group and mimics negative control group. HE staining was used to observe the morphological changes of the cells in each group. The alanine aminotransferase(ALT) and aspartate aminotransferase(AST) contents in each group were detected by the Lai method. The mRNA expressions of miR-21 and nuclear factor κB(NF-κB), tumor necrosis factor α(TNF-α) and interleukin-6( IL-6) genes were detected by RT-PCR. The expression of NF-κB protein in each group was detected by Western blot. The expression levels of TNF-α and IL-6 in each group were detected by ELISA. Results Compared with the control group, the expression of miR-21 was up-regulated in the drug group, and the mRNA and protein levels of NF-κB, TNF-α and IL-6 were elevated. Overexpression of miR-21 upregulated the mRNA and protein expression of the inflammatory regulatory factor NF-κB, while the mRNA and protein levels of inflammatory factors TNF-α and IL-6 further increased. Interfering with miR-21 reduced the mRNA and protein levels of NF-κB, TNF-α, and IL-6(allP<0.05). Conclusion The expression of miR-21 is up-regulated in anti-tuberculosis drug-induced liver injury cells. Down-regulation of miR-21 can reduce the expression of inflammatory factors to alleviate hepatocyte injury.