Objective To investigate the correlation between serum interleukin-2 receptor(IL-2R),CD4+/CD8+ and disease activity in patients with lupus nephritis(LN).Methods A total of 38 patients with LN who were treated in Hangzhou Hospital of Traditional Chinese Medicine Affiliated to Zhejiang Chinese Medical University from March 2021 to December 2022 were enrolled in LN group,and 40 healthy persons who underwent physical examination in the hospital during the same period were included in healthy control group.General clinical data,systemic lupus erythematosus disease activity index(SLEDAI)and pathological classification were collected.LN patients were divided into active group and inactive group according to SLEDAI score,and the difference of clinical indicators between two groups was compared.Results The hemoglobin(Hb),platelet count,albumin(ALB),complement C3 and C4 in LN group were significantly lower than those in healthy control group,the positive rates of antinuclear antibody and anti-double strand DNA antibody(anti-ds-DNA antibody),serum creatinine(SCr)and C-reactive protein were significantly higher than those in healthy control group(P<0.05).The ALB of active group was significantly lower than that of inactive group,and IL-2R,erythrocyte sedimentation rate,24h urinary protein quantity and anti-ds-DNA antibody positive rate were significantly higher than those of inactive group(P<0.05).Serum IL-2R levels in LN patients were positively correlated with SLEDAI,SCr,blood urea nitrogen and 24h urinary protein quantity,and negatively correlated with Hb and complement C3(P<0.05).Conclusion Serum IL-2R can be used as an indicator to judge the degree of LN activity and provide a basis for the judgment of clinical disease activity.