To explore the clinical diagnosis methods of SARS virus infection, and analyze the value of ELISA by which the SARS-Ab was detected. The results show ed that the control group was negative, the positive detection rate was respective ly 2.7% and 92% before and after 12 days when the patients got the SARS in the t est group, and the total positive rate was 94.4%. But the detection rate was 3 1% among 29 suspected patients. In a word, the ELISA method was high specified. Th e detection rate was lower before 12 days and higher after 13 to 16 days when th e patients got the SARS.