Objective To study the molecular mechanism of Celastrus orbiculatus extract on liver cancer metastasis. Methods Human liver cancer HCLM6 cells were grown and passaged in the culture medium and the logarithmic growth phase cells were selected. The Celastrus orbiculatus extract group was divided into 10 mg/L

20 mg/L

40 mg/L

80 mg/L and 160 mg/L concentrations. The positive control group was given 180 mg/L 5-fluorouracil （5-FU） injection and the negative control group was not treated. The effects of Celastrus orbiculatus extract on the proliferation and migration of HCCLM6 cells were observed. The expression of vascular endothelial growth factor-C （VEGF-C） was observed as well. Results The inhibition rate of cell proliferation at 160 μg/ml was the highest after 24 hours and 48 hours of administration in the Celastrus orbiculatus extract group （P<0.01）. Comparing with the negative control group

the penetrated cells in the Celastrus orbiculatus extract group and positive control group were significantly decreased （P<0.01）. Comparing with the positive control group

the penetrated cells at 10 μg/ml

20 μg/ml

40 μg/ml and 80 μg/ml in the Celastrus orbiculatus extract group were significantly increased with a dose-dependent manner （P<0.05 or P<0.01）. Comparing with the negative control group

the contents of VEGF-C protein were significantly decreased in the Celastrus orbiculatus extract group and positive control group （P<0.05 or P<0.01）. Conclusion Celastrus orbiculatus extract can inhibit the proliferation and migration of HCCLM6 cells and down-regulate the expression of VEGF-C

which might be part of the mechanism of celastrus orbiculatus extract on cancer metastasis.