ObjectiveTo investigate the survival of liver cancer cells in hypotonic solution, and provide a theoretical basis for the clinical application of warm distilled water to kill free intraperitoneal liver cancer cells. MethodsThe hepatocellular carcinoma cell line Hep3B were cultured by using different osmotic HEPES buffered solution (148 mOsmol/kg, 90 mOsmol/kg, and 0 mOsmol/kg) in vitro, and then the activity and status of the cells were observed by using the MTT assay and flow cytometry. ResultsOne hundred and forty-eight mOsmol/kg and 90 mOsmol/kg osmotic pressure solution had no obvious killing effect for hepatocellular carcinoma cell line Hep3B, the cells still had strong activity after 30 min. The 0 mOsmol/kg osmotic pressure distilled water had particular killing effect for hepatocellular carcinoma cells, with the prolongation of time and the killing effect was enhanced. It needs 10 min to destruct free cancer cells. ConclusionApplication of warm distilled water lavage in liver cancer surgery requires the continuing role of 10 min to kill the intraperitoneal free cancer cells, thereby preventing the occurrence of postoperative peritoneal metastasis.