Abstract: Surgical excision is an important treatment for tumors. Tumor metastasis is the critical cause of death for cancer patients. The balance between the metastasis propensity of tumor and the defense function of the body determines the possibility of tumor metastasis. The entire cellular immune system is the main host defense against metastasis progression. Natural killer cells, which can recognize and kill cancer cells spontaneously, are the first defence against tumor cells. Surgery can decrease the defenses of the body and induce stress response. Anesthesia is an effective method to reduce stress response induced by surgery. Different anesthesic techniques and anesthetic drugs influence the immunologic function of cancer patients and may affect the development of metastasis. The effects of volatile anesthetics, intravenous anesthetics, opioids, and local anesthetics on the immune function and tumor metastasis are discussed in this study. However, the effect of regional anesthesia is better than general anesthesia for cancer metastasis.