Based on the study of an indicator index system that depicts the epidemic situation of Severe Acute Respiratory Syndrome (SARS), this paper proposes an approach to divide the epidemic process of SARS into four typical stages, and studies the character of every stage of the indicator index. According to the indicator index system, the paper compares the epidemic situation of Beijing with that of Hong Kong, analyses the spreading rules of SARS and validate the validity and rationality of the statistical method when it is used in large-scale malignant epidemic disease. The thought and method this paper puts forward have certain enlightenment and reference to statistics and analysis of similar malignant epidemic diseases.