Objective To investigate the expression of Aiolos transcription factor in peripheral blood mononuclear cells （PBMCs） from patients with systemic lupus erythematosus （SLE）, and to explore their clinical significance. Methods Western blot was performed to detect the protein expression of Aiolos transcription factor in PBMCs from 19 patients with active SLE, 13 patients with stable SLE and 30 healthy volunteers. The relationship between the expression of Aiolos transcription factor and SLE disease activity index （SLEDAI） was analyzed. Results A significant difference was noted in the relative expression of Aiolos transcription factor between SLE patients and normal controls （0.56 ± 0.17 vs 0.81 ± 0.09, P < 0.01） and between patients in active stage and those in stable stage （0.52 ± 0.14 vs 0.65 ± 0.19, P < 0.05）. In addition, the expression level of Aiolos protein was negatively correlated with SLEDAI in patients（r = -0.65, P < 0.01）. Conclusion A decrease is observed in the expression of Aiolos transcription factor in SLE patients, which is correlated with the disease activity in SLE.