Abstract: Systemic lupus erythematosus(SLE) is a complicated autoimmune disease characterized by aberrant B cell activation. Belimumab is a human monoclonal antibody, which can reduce active B cells through binding to the B-cell-activating factor of the tumor necrosis factor family(BAFF). In 2011, the US Food and Drugs Administration approved belimumab as a new drug option for SLE patients. This article mainly discusses the mechanism and relevant clinical trials of belimumab and looks forward to its future.