RT-qPCR analysis showed that the gene level of TGF-β was upregulated in MCD-diet mice liver, at the same time, its transduction signal pathway Smad 3 and its downstream genes ACTA2 and COL1A1 were also upregulated, which indicating that TGF-β/Smad signaling pathway was a important mechanism in MCD-diet induced liver fibrosis. The gene discussed is ACTA2; the disease is Hepatic fibrosis.