Objective: To investigate the therapeutic effects of stereotactic radiotherapy for retroperitoneal metastatic tumor. Methods: From August 1997 to October 2004, 44 patients with retroperitoneal metastatic tumors were treated with stereotactic radiotherapy. The planning target volume was encompassed by 90%–95% isodose line. Fractional dose was from 6 Gy to 8 Gy, and they were treated 2–3 times per-week and 4–8 times in all. The total radiation doses of PTV were from 32 Gy to 48 Gy. Re- sults: After the radiotherapy, the pain was obviously relieved in 81.8% patients. Three months after completion of radiotherapy passed and then, abdominal CT was performed to evaluate the results. The whole effective rate was 81.8% [CR 27.7% (12/44) and PR 54.5% (24/44)], and six months after radiotherapy, CR was 27.7% (12/44) and PR was 59.1% (26/44). The middle survival time was 12 months. Conclusion: It is suggested that stereotactic radiotherapy for retroperitoneal metastatic tumor is a safe and effective method.