Xanthoceraside is a component obtained in the husks of Xanthoceras sorbifolia Bunge. Series of researches proved that xanthoceraside had functions of anti-inflammation and anti-tumor effects. However, the mechanisms of xanthoceraside against bladder cancer are unclear. Accordingly, we proposed to investigate xanthoceraside's impacts and potential mechanisms in cells of bladder cancer. By using the CCK-8 assay, we measured the viability of cells. With the use of 4,6-diamidino-2-phenylindole (DAPI) staining, we examined nuclear fragmentation and chromatin condensation in the nuclei of apoptotic cells. By using flow cytometry, we measured cell apoptosis. By using Western blotting, we tested the expressions of Caspase-9, Caspase-8, Caspase-3, Bcl-xL, P53, and PI3K/Akt/Bcl-2/Bax. The proliferation of cell lines of human bladder cancer T24 and 5637 was suppressed by xanthoceraside significantly in a time- and concentration-dependent way. When cell lines 5637 and T24 were incubated as the xanthoceraside dose increased, the rates of cell apoptosis were upregulated, which was dependent on dose. According to further analysis, xanthoceraside induced apoptosis by upregulating Bax and downregulating the expression of Bcl-xL and Bcl-2. However, xanthoceraside did not change the expression of Caspase-9, Caspase-8, and Caspase-3. Interestingly, xanthoceraside also downregulated the expression of p-PI3K and p-Akt, and upregulated P53. Xanthoceraside induces cell apoptosis through downregulation of the PI3K/Akt/Bcl-2/Bax signaling pathway in cell lines of human bladder cancer.