Abstract: After delimiting the boundaries of Eastern Asiatic genera (mainly Sino-Himalayan & Sino-Japanese ones) in Yunnan, we concluded as follows: (1) In general, ' Tanaka Line' is a real one which is effectively delimited the eastern boundaries of Sino-Japanese genera & the western boundaries of Sino-Himalayan ones; (2) In comparision with the Sino-Himalayan genera, the Sino-Japanese ones are more strict to ' Tanaka Line'. Furthermore, we discussed the origin cause of ' Tanaka Line'& its significance in the study of florististic regionalization in Yunnan and the delimitation of species.

Key words: Tanaka Line