Intrahepatic cholangiocarcinoma (ICC), an aggressive liver cancer, lacks simple and accurate clinical tests, which poses challenges to postoperative diagnosis and treatment. Recent studies have indicated that platelet levels might be relevant to the postoperative prognosis of ICC. However, their prognostic significance in ICC remains unclarified. This study included 218 ICC patients who underwent hepatic resection. Comprehensive analyses of patients' postoperative prognosis were conducted primarily focusing on their platelet levels associated with prognostic traits. To further investigate the underlying mechanism between platelet levels and patients' postoperative prognosis, we elucidated the association between platelets and tumor metastasis using HCCC-9810 and HUCC-T1 cells as well as mouse models. In the retrospective cohort study, elevated serum platelet levels (≥300 × 10