Sharing the same origin, Japanese Kampo medicine and traditional Chinese medicine both pay great attention to the constitutional differences between individuals. Extensively studied in Japan, constitutional medicine has a lot of schools and classifications, in which Yi Guan Tang medicine is a typical representative of Japanese constitutional research. Both constitutional medicine of traditional Chinese medicine and Yi Guan Tang medicine believe that constitution is associated with the development of diseases; however, there are differences in theoretical origin, classification, pathogenesis, and diagnosis and treatment between the two systems. These two systems are closely related to each other, and mutual communication and reference should be enhanced in the future.