n order to reveal the actual pathomorphological changes of theroutine description such as pathological terms: slight, moderate or severeactivity of germinal center immunoblasts in lymph node, and slight,moderate or severe deposition of immune complex in germinal center. Thetheory of Fuzzy Mathemat ics was introduced to computer recognizingsystem.This system might study pathological pattern with Fuzzy Char-acters on the basis of accumulative experience. In this paper we haveused the above system to express lymph nodes' pathological changes inthe paper of "Establishment of SIV SAIDS and lts Treatment withChinese Medicince" .By the use of this system a good fuzzy characterappeared and also be used to examine the SIV quantity and amount ofimmune complex in lymph nodes.