Non-Hodgkin's lymphoma (NHL) is one of the common hematological malignancies,and diffuse large B cell lymphoma (DLBCL) is the most common type of NHL in adults.The clinical manifestations of DLBCL are highly heterogeneous,and the prognosis is significantly different.The exact pathogenesis of DLBCL is still unknown,however numerous researches indicate that DLBCL development is closely related to the autoimmune disorders.T lymphocytes are the most critical cells in the immune system,in which CD4+ T cells play a most important role in the immunoprotection.At least four CD4+ T cell subsets have been found so far,they are Th1,Th2,Treg and Th17 cells,respectively.Several recent studies have reported that Th17 cells play an important role in the development of DLBCL.The relationship between DLBCL and Th17 cells is controversial,and more studies have found that Th17 cells play a protective role in the tumor microenvironment of DLBCL.Therefore,understanding the relationship between Th17 cells and DLBCL may help us to discover a new biological immunotherapy.This article will review the regulation role of Th17 cells in the development of DLBCL.