Abstract: Peripheral T-cell lymphoma-unspecified (PTCL-U) is a new subtype based on WHO classification of lymphoid neoplasms. PTCL-U is a group of malignancies originating from post- thymic T-cells, with poor prognosis and without ideal therapeutic regimen. Recent reports suggest that it is as-sociated with EBV and HTLV-Ⅰ. The diagnosis for the disease requires the characteristics of clinical symptoms, histology, phenotype and genotype feature, with exception of others specified T-cell lym-phomas. Current treatment modalities for PTCL-U patients can 't achieve satisfactory outcomes, and the 5-year overall survival rate is approximately 22%-27%%. The optimal therapy for the patients needs tobe explored.