Abstract: OBJECTIVE To investigate the detection significance of lymphocyte subsets, CD₆₄ index and related clinical indexes for patients with systemic lupus erythematosus secondary infection, so as to provide references for clinical treatment. METHODS A total of 122 cases of systemic lupus erythematosus in our hospital from Jan. 2013 to Dec. 2014 were chosen as the research objects. According to whether or not with secondary infection, the patients were divided into infection group and non-infection group, with 61 cases in each group. The CD₆₄ index and immune indexes of the two groups were observed and compared. RESULTS The CD₆₄ index, PCT, IL-6, and TNF-αof infection group were (7.73±1.92), (0.78±0.21) ng/mL, (65.32±21.34) ng/L, and (29.93±10.34) pg/mL, which were all higher than those of non-infected group. The immune system indexes of CD₃⁺, CD₄⁺, CD₄⁺/CD₈⁺, and NK cells were all significantly lower than those of non-infected group. The CD₈⁺ level of infection group was significantly higher than that of non-infected group (P＜0.05). CONCLUSION The monitoring for these indicators is help to master the clinical infection of patients.