Objective To explore the effect of aspirin on the apoptosis and autophagy of human epidermal growth factor receptor 2 (HER2)-positive AU-565 breast cancer cells and triple negative MDA-MB-231 breast cancer cells. Methods MTT assay was performed to detect the effect of aspirin on cell proliferation of cancer cells; flow cytometry was performed to assess the effect of aspirin on cell apoptosis; Western blotting was used to determine the protein expressions of apoptosis-related proteins Bcl2, cleaved caspase-3 (c-caspase-3), cleaved PARP (c-PARP) and autophagy-related gene 3 (ATG3), LC3A, LC3B. Results Aspirin inhibited the proliferation of AU-565 and MDA-MB-231 cells and increased the cell apoptosis. The expressions of c-caspase-3 and c-PARP were up-regulated, the Bcl2 was down-regulated, and ATG3, LC3A, LC3B were also significantly up-regulated. Conclusion Aspirin can inhibit the proliferation of AU-565 and MDA-MB-231 breast cancer cells via inducing cell apoptosis and autophagy.