Abstract: Serum AnDNA levels detected by ESN and clinical observation of 100 cases of SLE in different periods were analylized.It was found that the positive rates of ESN were 65.0% in all patients and 92.2% in patients in active period.The positive rates and geometric mean of positive titers decreaxd consistently with the improvement of patient's condition.The positive rates in different periods differed significantly.In the ESN poitive group,the incidence of renal involvement was higher than that of negative group.The clinical alleviative rate was 77.8% in persistently negative group.It is the author's option that ESN is of great value for the diagnosis,evaluation of activity,therapeutic effect and estimation of prognosis in SLE.