As a global health threat, bladder cancer (BC) is a common urological disease characterized by a high risk of progression and recurrence. Icariside II (ICA-II), a flavonol glycoside, exhibits antitumor ability in various tumors. However, there is no systematic study exploring the pharmacological mechanism of ICA-II in BC. We used public databases to obtain potential targets of ICA-II and related genes in BC. Bioinformatics analysis and molecular docking were used to identify potential targets and signaling pathways. Then, MTT, cell cycle assays and western blot (WB) were used to validate the predicted pathways in bladder cell lines, and in situ bladder cancer models were also established to verify the effect of ICA-II. Our research demonstrated that these ICA-II hub genes were related to the cell cycle. Then, our molecular docking analysis confirmed the interaction between ICA-II and CCNB1. In addition, our in vitro experiment demonstrated that ICA-II restrained the proliferation of BC cells mainly by blocking the cell cycle. WB also verified that ICA-II decreased the expression levels of CCNB1. In situ BC models showed that ICA-II had no hepatotoxicity or nephrotoxicity and could suppress the growth of in situ BC. In summary, during this study, we found that ICA-II had low toxicity in the kidney and liver. Network pharmacology was used, and both cell and animal experiments verified that ICA-II has a good therapeutic effect on bladder cancer, which may inhibit the proliferation and progression of bladder cancer by blocking the cell cycle of BC cells.Copyright © 2023 Elsevier B.V. All rights reserved.