BACKGROUND: Apoptosis inhibitory protein Bcl-2 binds to Beclin 1 gene. Effects of expression and function of Beclin 1 gene on four colon cancer cell lines (HT29, Developmental Learning Department-1, SW480, SW620). Materials and Methods: The expression of Beclin 1 mRNA was detected by RT-PCR, and the transfected Beclin 1 gene was introduced into HT29 colon cancer cells with low expression. In addition, the effect of changing cell cycle was evaluated by flow cytometry and the expression level of cell cycle-related proteins in Beclin 1 transfected colon cancer cell lines. Results: The expression levels of Beclin 1 mRNA in colon cancer cell lines were different. Down-regulation of gene expression in colon cancer cell line Beclin 1 leads to cell growth inhibition. Cell cycle analysis showed that the percentage of connected cells was significantly higher than that of cells transfected with Beclin 1 The expression levels of cyclin E and Rb decreased. Conclusion: Beclin 1 has inhibitory effect on colon cancer cells.