A study on the green naturality and flora were conducted in the five watersheds of Yeongsan river system during the period of 1979 to 1984. Totality of green nature in each surveyed watershed was transformed to degree of green naturality which is one of the barometers indicating the content of preserved waters; in natural vegetations. In the Damyang watershed the average degree of green naturality(ADGN) was 6.97 which is the highest among surveyed watersheds and consider as natural state preserved with abundant water contents. The ADGNs were recognized as 6.19, 6.03, 5.38 and 5.28 for Changseong, Gwangju, Bulgap and Naju watersheds, respectively. Nine different grades of green naturality; 0, 1, 2, 3, 5, 6, 7, 8 and 9 have teen registered. The number of vascular plant investigated in these watersheds was a total of 782 kinds belonging to 119 families, 446 genera, 766 species, 14 varieties and 3 forms. Floristic composition of the Naju watershed was indicated the transitional zone of subtropical and temperate flora.