In this course, comparison between traditional Chinese medicine (TCM) and Western medicine is made based on diagnostics. First of all, the Western medical diagnostics is based on its pathology will be reviewed; meanwhile, the diagnostics of TCM that is focused more on identification of the present state of patients. The former is focused on the structure change, while the latter more of the changes of functions. Secondly, we will discuss and evaluate the influence of homeostasis in diagnostics. Thirdly, the theories of diagnostics in TCM will be examined. Fourthly, the diagnostics of TCM will be represented quantitatively under the chaotic wave theory of fractal continuum. To illustrate the effectiveness of TCM diagnostics, several disorders of medicine will be presented and discussed. As a result, the TCM diagnostics can be better appreciated.