Abstract: Th17 cells have recently been classified as a new effector T-cell subset which is distinct from Th1, Th2 and Treg subsets. Since Th17 cells were found, studies confirmed that these cells had critical roles in infection, inflammation, autoimmune diseases, and graft versus host disease. Moreover, Thl7 cells have been recently found in some human cancers, but the differentiation and development condition, regulation mechanisms and functional effects of Th17 cells remains controversial. This review summarizes recent findings regarding the correlation of Thl7 cells and malignant tumor related cytokines with tumor immunity.