Objective: To investigate the anti-metastatic effects of ethyl acetate extracts from Callicarpa nudiflora (ECN) and its mechanisms. Method: BALB/c Nu mice were used to establish in vivo experimental metastasis mode and the mice were randomly divided into control group and ECN groups treated with 0.125, 0.25, 0.5 g· kg^-1 ECN respectively. After 8 weeks of gavage (once a day), human cytokeratin 19(CK19) mRNA expression in lungs of mice was checked by nest PCR to determine effects of ECN on the formation of lung metastatic foci of breast cancer. In vitro invasion and migration assay were involved to determine effects of ECN on metastatic properties of breast cancer cells. MDA-MB-231 cells were treated using ECN at dose of 100, 200 mg· L^-1 and BB-94 with the final concentration of 10 nmol· L^-1(n=4). After 14 h incubation, the invaded and migrated cells were calculated. In vitro adhesion assay was also used in this study. MDA-MB-231 cells were treated using ECN at dose of 100, 200 mg· L^-1and BB-94 with the final concentration of 10 nmol· L^-1(n=3). After 60 min incubation, cells attached to matrix proteins were detected. p-Snail and E-cadherin expressions were checked by western blot method in current study to detect the effects of ECN on activation of Snail in MDA-MB-231 cells, which were treated with 100, 200 mg· L^-1ECN for 24 h. Result: ECN induced a significant decrease on human CK19 mRNA expression in lung of tumor-bearing mice(P<0.01). Moreover, in vitro adhesion, migration and invasion of MDA-MB-231 cells were inhibited significantly when these cells incubated with ECN (P<0.01). It was also showed that ECN affected activity of Snail and expression of E-cadherin in breast cancer cells. Conclusion: ECN shows significant anti-metastatic properties. The mechanisms of action of ECN may be associated with suppression of Snail activation.