Objective: To explore serum angiogenic factor expression in patients with osteosarcoma and its relationship with metastasis. Methods: Immunohistochemistry was used to test the expression of CD34 and FVIII-Rag in osteosarcoma tissues of 36 patients (osteosarcoma group) and microvessel density (MVD) was also recorded. In addition, ELISA was used to test the level of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), transforming growth factor-${eta}1$ (TGF-${eta}1$) and endostatin (ES) in the osteosarcoma group and in a control group. Results: VEGF and ES level were significantly higher than in the control group before operation (P<0.01), VEGF, bFGF and TGF-${eta}1$ correlating with the ES level (P<0.01). Serum VEGF and ES levels of osteosarcoma patients before surgery were closely related to relapse and metastasis; moreover, serum VEGF increased with MVD (P<0.01). Postoperative VEGF and ES levels were lower than the preoperation values (P<0.01); ES level in relapse group was significantly higher than that of the non-relapse group (P<0.01). Conclusion: Preoperative serum VEGF and postoperative ES levels have great predictive value with regard to relapse of osteosarcoma patients.