Abstract: Objective To observe the efficacy and safety of belimumab for lupus nephritis(LN) in real world.Methods For this retrospective and real-world clinical trial, 25 LN patients received belimumab from September 2020 to May 2022.Through comparing the changes in clinical parameters and observing adverse events before and after treatment, efficacy and safety of belimumab were observed.Results After a therapy of belimumab, anti-dsDNA antibody titer declined markedly(χ²=14.000, P=0.007) and complement C3 spiked sharply(F=3.228, P=0.0172) at different follow-up timepoints.After therapy, urinary protein-to-creatinine ratio(uPCR), urinary red blood cell count, SLEDAI score and dosage of oral corticosteroid dropped markedly and blood albumin and hemoglobin levels rose.And the differences were all statistically significant between baseline and values at Week 52.In addition, SLEDAI score(F=12.23, P<0.001) and dose of oral corticosteroid(F=13.57, P<0.001) were both statistically significant.During a therapy of belimumab, 6 patients reported such adverse events as infection(n=4) and leucopenia(n=2).All of them were cured and there was no onset of serious adverse events.Conclusions Belimumab is both safe and efficacious for LN.The occurrence of adverse events such as infection and leukopenia should be closely monitored during therapy.