In order to explore the regulatory effects of metformin on the proliferation, migration and TGF-β1/Smads signaling pathway of human liver cancer cells, human liver cancer MHCC97H cells were cultured in vitro. They were divided into control group (no intervention), 1.25, 2.50, 5.00 mmol/L metformin group and inhibitor group (5.00 mmol/L metformin +10 μmol/L LY2109761). In this study, the cell viability of 5.00 mmol/L metformin group was close to 50%, hence 5.00 mmol/L metformin was selected as the optimal concentration. Cell counting kit-8 (CCK-8), 5-acetylidene-2' deoxyuracil riboside (EdU), Transwell chamber, real-time fluorescence quantitative PCR (RT-qPCR) and Western blot were used to analyze the proliferation activity, proliferation rate, migration ability and expression levels of related factors of human hepatocellular carcinoma MHCC97H cells. Compared with the control group, the proliferation activity and proliferation rate of 2.50 and 5.00 mmol/L metformin groups and inhibitor groups decreased (P<0.05). The cell migration number, TGF-β1 and p-Smad3 protein expression levels, N-cadherin, vimentin and fibronectin (FN) mRNA and protein expression levels of 1.25, 2.50 and 5.00 mmol/L metformin groups and inhibitor group decreased compared with the control group. The expression level of p-Smad7 protein, E-cadherin mRNA and protein significantly increased, and the changes were more significant with the increase of concentration (P<0.05). Compared with 5.00 mmol/L metformin group, the addition of inhibitors in the inhibitor group made the changes of all indexes more significant (P<0.05). The inhibition of metformin on the proliferation, migration and epithelial-mesenchymal transformation (EMT) of MHCC97H cells of human liver cancer depends on the inhibition of TGF-β1/Smads pathway, which provides a reference for the study of liver cancer.