To extract four types of Quercus infectoria galls(QIG) extracts using solvents with different polarities and screen for the optimal QIG extract with the highest inhibitory activity against colon cancer cells.Methods:QIG extracts were obtained by reflux extraction for three times using eight-fold solvents，with each extraction performed for 0.5 hours.The resulting extracts were concentrated and dried to prepare QIG extracts in acetone，ethanol，methanol，and water.The chemotherapy drug 5-fluorouracil was used as a positive control.The CCK-8 assay was used to evaluate the inhibitory effects of the active extracts and gallic acid at different concentrations and incubation periods on HCT-116 and Caco-2 colon cancer cells in vitro.Results:The four QIG extracts and gallic acid exhibited varying degrees of inhibitory effects on the two colon cancer cell lines.The IC50 values of the four extracts against HCT-116 cells at 12，24，48，and 72 hours were 0.313～0.988 mg/mL，0.131~0.53 mg/mL，0.107~0.379 mg/mL，and 0.1~0.262 mg/mL，respectively.For Caco-2 cells，the IC50 values were 1.093~1.382 mg/mL，0.404~0.53 mg/mL，0.246～0.341 mg/mL，and 0.134~0.312 mg/mL，respectively.Among them，the ethanol extract showed the best inhibitory effect on both cell lines.At 72 hours，the maximum inhibition rates and IC50 values of the ethanol extract on HCT-116 and Caco-2 cells were 76.55% and 0.1 mg/mL，and 78.8% and 0.134 mg/mL，respectively.Gallic acid showed maximum inhibition rates and IC50 values of 86.54% and 0.07 mg/mL，and 80.3% and 0.083 mg/mL，respectively，at 72 hours.Conclusion:QIG extracts obtained using solvents with different polarities exhibited varying degrees of inhibitory effects on HCT-116 and Caco-2 colon cancer cells.Among the extracts，QIG ethanol extract showed the most promising inhibitory effects on both cell lines.