To investigate the protective effect and mechanisms of Rongmu Fugan Formula(RMFGF) on cholestatic liver injury(CLI).Methods:A cholestasis mouse model was established by oral administration of α-naphthyl isothiocyanate(ANIT)，and an in vitro model was induced in L02 cells with glycochenodeoxycholic acid(GCDCA).The study groups included a normal group，model group，high，medium，and low-dose RMFGF groups，a positive control group with ursodeoxycholic acid(UDCA)，and a high-dose RMFGF+MCC950 [nucleotide-binding oligomerization domain-like receptor 3(NLRP3) inhibitor] group.Hematoxylin and eosin(H&E) staining was used to observe liver tissue pathological changes.Biochemical methods were applied to detect liver function and oxidative stress markers，and enzyme-linked immunosorbent assay(ELISA) was used to measure the levels of inflammatory mediators.Immunohistochemistry was used to observe the expression of NLRP3 inflammasome，and Western blot was performed to analyze the expression of NLRP3 pathway proteins and apoptosis-related proteins.Cell viability was assessed by CCK-8，reactive oxygen species(ROS) levels were measured using specific kits，and TUNEL assays were used to detect the level of cell apoptosis.Results:After treatment with RMFGF，liver function parameters，NLRP3 inflammasome expression，oxidative stress markers，inflammatory mediator levels，and cell apoptosis were dose-dependently reduced both in vivo and in vitro.Conclusion:RMFGF inhibits inflammation and oxidative stress，reduces cell apoptosis，and thereby ameliorates CLI.The mechanism of action is associated with the suppression of the ROS/NLRP3 pathway.