Inspection of the complexion is one of the characteristics of traditional Chinese medical diagnosis. Traditional Chinese medicine puts high emphasis on inspection of the complexion and there exists detailed discussion on inspection of facial expression in Neijing. The so-called inspection of facial expression is a method to diagnose diseases according to the theory of five Zang-organs matching five elements and five colors by distinguishing various changes of facial color, such as green, red, yellow, white and black based on yin and yang doctrine and five elements theory. Nowadays, more and more experts have introduced color optical theory and modern devices into the modern research field of traditional Chinese medical diagnosis with the development of color optical theory and the renewal of determining devices, such as digital camera, color differentiation meter and spectrophotometer, to make the research more scientific and objective and avoid the deviations caused by human factors. The modern study of traditional Chinese medicine diagnosis has made fare progress, consequently enriching the contents of its facial color observation and giving a more scientific explanation of it. However, the devices being used now are still disunited; the data may be unilateral and cannot contain the whole information. So the most important task is to invent and use scientific devices conforming better with the theory of five colors observation in traditional Chinese medicine.

Key words: Skin color inspection, Neijing, Objectifying four diagnosis methods, Equipment, Color determination