This study aims to investigate the effects of targeted regulation of Mst1 (Mammalian sterile 20-like kinase 1) expression on the proliferation and apoptosis of SW480 colorectal cancer cells and to elucidate the mechanisms underlying these effects. PolyJetTM in vitro DNA transfection reagent was used to transfect pEGFP-N1-Mst1 into SW480 colorectal cancer cells, and LipofectamineTM2000 was used to transfect Mst1-specific siRNA for the targeted silencing of Mst1. MTT assay was then performed to detect the survival rate of the cells, flow cytometry was used to determine apoptosis, and RT-qPCR and western blot were used to measure the mRNA and protein levels of Mst1, PUMA, p73, p53, YAP (Yes Associated Protein 1), and caspase-3. Compared with the control group, the p-EGFP-Mst1 and p-EGFPMst1+ 5-FU groups showed significantly higher rate of cell proliferation inhibition and apoptosis (P<0.05). The protein levels of MST1, Phospho-YAP1 (Ser127), P73, P53, PUMA, and Caspase-3 were significantly increased (P<0.05), while the protein levels of CTGF (Connective Tissue Growth Factor) and AREG (Amphiregulin) were significantly reduced (P<0.05). In the Mst1-siRNA group, the apoptosis rate was significantly decreased (P<0.01), cell proliferation was accelerated, p73, p53, and PUMA were downregulated, and CTGF, AREG, and YAP were upregulated. The targeted regulation of Mst1 expression significantly affected the proliferation and apoptosis of the SW480 cells. Thus, Mst1 has potential for use as a new target for the prevention and treatment of colorectal cancer.