Objective To analyze the relationship of serum levels of Arg-1，iNOS，and VEGF with clinical characteristics in patients with peripheral T-cell lymphoma（PTCL）. Methods We compared ELISA-determined serum levels of Arg-1，iNOS，and VEGF in peripheral blood in 25 patients with PTCL before and after chemotherapy. As a control， we measured the same serum levels in 15 healthy individuals. Results PTCL patients showed significantly higher serum levels of Arg-1，iNOS，and VEGF than healthy controls （P＜0.05）. Serum levels in patients decreased significantly after chemotherapy （P＜0.05）. Elevated serum levels of Arg-1，iNOS，and VEGF correlated with extranodal involvement，bone marrow involvement，bulky disease（diameter >10 cm），disease stages Ⅲ-Ⅳ and 3 to 5 IPI score（P＜0.05）. However， elevated serum levels of the three factors did not correlate with age or LDH level（P＞0.05）. Conclusion In PTCL，elevated serum levels of Arg-1，iNOS，and VEGF may correlate with worse clinical characteristics，and chemotherapy can significantly reduce the levels. This three factors may closely correlated with the occurrence and progression of PTCL.