Abstract: ［Abstract］Objective　To study the clinical effects of umbilical cord derived mesenchymal cell transplant on patients with lupus nephritis，and to elucidate the clinical effects and mechanisms of action．Methods We conducted a random, double blind，contrast control that involved 12 SLE patients（1）control team: standard treatmen（2）hUC-MSC treatment team: weekly intravenous pulse for two weeks. We investigated the clinical symptoms, physical signs and adverse effects before treatment，two months and six months after infusion of hUC-MSC．Data on serum biological markers of renal damage（anti-C1q，Osteopontin（OPN），cellular inflammatory markers（IL-4，IL-6，Il-10，IL-17，IL-18，INF-Y，TGF-β1） as well as flow cytometry measurements of T cell sub groups（CD3，CD4， CD8）were taken at baseline，then again at 2 weeks and 6 weeks post treatment．Results（1）Clinical manifestations and physical signs : the clinical manifestations and physical signs of patients in two groups were improved 2 and 6 months after treatment, and the cases of remission in treatment team were more than the control team, but there was no statistically significant difference（P＞0.05）. （2）SLIDAI score： there was a statistically significant difference in SLIDAI between the treatment teamand the control team（P＜0.05）. （3）Mechanisms of action: the levels of inflammatory （INF-Y， IL-4， IL-10， IL-6， IL-18） and renal injury markers （anti C1q and osteopontin） at 2 and 6 months after treatment in both groups decreased compared to baseline, but there was no statistically significant difference between two teams（P＞0.05）. （4）T-Lymphocyte Subsets: there were statistically significant differences in CD4+T and CD8+T cells between before treatment and 2 and 6 monthsafter treatment in both teams（P＜0.05）, but there was no statistically significant difference between two teams（P＞0.05）. Conclusions（1）The clinical symptoms and laboratory examination results of patients in two teams were all improved, but there is no statistically significant difference between two teams. （2）There is no statistically significant difference in the inflammatory cytokines and renal injury markers between before and after treatment in two teams, Huc-MSC for treatment of LN still needs more clinical data.（3）Whether the Huc-MSC could reconstruct the balance of the T cell subgroups still needs further exploration.