Fibroblast growth factor 21 (FGF21) is a member of the FGF family and acts as a potent regulator of glucose and lipid homeostasis, but its effect on renal fibrosis and the underlying mechanisms are totally unknown. The purpose of this study was designed to investigate whether FGF21 has effect on high glucose-induced fibrogenesis in human mesangial cells (HMCs) and the underlying mechanism. High glucose is well known to stimulate the expression of extracelluar matrix (ECM) in human mesangial cells. In humans, overexpression and deposition of ECM lead to renal fibrosis. Thus, in this study, HMCs were incubated in high glucose with or without various concentrations of FGF21. Results demonstrated that the expression of FN, Col, TGF β1 and α-SMA were significantly up-regulated in HMCs. Whereas, treatment with FGF21 down-regulated the expression of FN, Col, TGF β1 and α-SMA. In addition, growth factors are considered to be an important driving force for the pathogenesis of renal fibrosis. Significantly increased PDGF, VEGF and CTGF expression were found in HMCs induced by high glucose. FGF21 treatments significantly decreased these growth factors expression by down-regulating the phosphorylation level of STAT5. Here, we reported for the first time that FGF21 decreases ECM expression by inhibiting STAT5 signal pathway and consequently decreasing the expression of PDGF, VEGF and CTGF.