Metastasis and recurrence of tumors is the chief cause of death for such patients. Therefore,researches on the mechanism of its metastasis, prevention and treatment are the focal points in the field of traditional Chinese medicine (TCM) and Western medicine (WM) at present. WM practitioners study on tumor metastasis involved its occurrence and development including every detail and process, and now it even has developed into the molecular biological field. In treatment surgical operation and radio- chemotherapy is used as the main means, but the efficacy is not too optimistic. In recent years, TCM, as part of the comprehensive therapy, has been gradually gaining attention of oncologists. Aimed at solving the difficult problems in metastasis of tumor, many TCM practitioners on the basis of syndrome differentiation have raised theories about the cause of tumor metastasis. On the basis of these theories, some TCM recipes against tumor metastasis have been developed to serve as an effective supplement to surgical operation, radio- and chemotherapy. The present article summarizes research results in recent years about the cause of formation of tumor and its metastasis by TCM and WM, so as to offer some theoretical clues to the study of tumors metastasis.