This paper analysed the data of epidemic encephalitis B incidence that was constituted to time- series and the two-ordered contingency table in Guangdong province from 1984 to 1993. Two different kinds of statistical methods of run- test and ordered-log-ratio test were applied to study the characteristics of seasonal distribution. Consistent conclusion was obtained to show that there appeared an obvious seasonal cyclic characteristic of a peak every year (June or July) for the incidence of epidemic encephalitis B. It is helpful for the epidemiologists to understand the principle and method of these statistical tests.