Objective: To study the efficiency and the mechanism of QI-LE polysaccharide (QI-LE), a new compound extracted from one kind of Chinese herbs with antiplatelet activity, against tumor metastasis in mice. Methods: QI-LE was prepared byour Lab. C57BL/6 female mice transplanted with H22 liver cancer cells were administered with the agent. Then the tumor nodules, pulmonary metastasis rate, and tumor cell proliferation activity were checked. Proliferation changes of tumor cells treated with different concentrations of QI-LE were also tested. Results: High and middle dosage of QI-LE could inhibit both the lymphatic and blood systemic tumor pulmonary metastases significantly, but not the tumor cell proliferation in vitro. Conclusion: QI-LE has antitumor metastasis activity, thus may be a new candidates for antitumor metastases agents.