Abstract: Venous blood from 7 female SLE patients and 5 normal females were cultivated in vitro.Each blood specimens was transferred into two containers; one served as a control and was irradiated with ultraviolet light after being cultivated for 24 hours, the other was cultivated for 72 hours without any treatment.It was found that the structural aberration rate of the lymphocyte chromosomes of the non-irradilated patient's blood specimens is 9.5 times that of the non-irradiated normal female (p<0.01),and the structural aberration rate of the lymphocyte chromosomes of the irradiated patient's specimens is 8.7 times that of the irradiated normal person (p<0.01).Whether the blood specimens were irradiated or not, no distinct difference on the structural aberration rates of the lymphocyte chromosomes was detected in the patient's specimens or the normal person.