〔Abstract〕 To investigate the impacts of remifentanil on the proliferation, apoptosis and Wnt/β-catenin pathway of breast cancer MDA-MB-231 cells. Methods Different concentrations of remifentanil (0, 0.5, 2.5, 5.0, 10.0, 20.0, 40.0 µg/mL) were used to treat human normal breast MCF-10A cells and breast cancer MDA-MB-231 cells to screen for experimental concentrations of remifentanil. MDA-MB-231 cells were divided into control group, remifentanil low (5.0 µg/mL), medium (10.0 µg/mL), and high (20.0 µg/mL) concentration groups, and remifentanil+SKL2001 (Wnt/β-catenin pathway agonist) group. MTT assay and colony formation assay were applied to detect cell proliferation ability. Flow cytometry was applied to detect cell apoptosis and cell cycle changes. Western blot was applied to detect protein expression related to cell proliferation, apoptosis, and the Wnt/β-catenin signaling pathway. Results Remifentanil at concentrations of 5.0, 10.0, and 20.0 µg/mL could reduce the viability of MDA-MB-231 cells and had no prominent toxicity to MCF-10A cells. Compared with the control group, the optical density value of cell proliferation, colony formation number, proportion of S-phase cells, and the protein levels of c-Myc, Cyclin D1, B lymphoblastoma 2 (Bcl-2), precursor of cysteine aspartate protease-3 (pro-caspase-3) and β-catenin were lower in the low, medium, and high concentration remifentanil groups (P<0.05), while the proportion of G0/G1 phase cells, apoptosis rate, early apoptosis rate, the protein levels of Bcl-2 associated X protein (Bax) and cleaved cysteine aspartate protease-3 (Cleaved caspase-3), and glycogen synthase kinase-3β (GSK-3β) were higher (P<0.05). SKL2001 could weaken the effects of remifentanil on the proliferation and apoptosis of MDA-MB-231 cells. Conclusion Remifentanil inhibits the proliferation of MDA-MB-231 cells, induces apoptosis and cell cycle arrest, and its mechanism may be related to the inhibition of Wnt/β-catenin signaling pathway activation.