After the opening of Gosu - cave, as tourist has increased, the inner parts and outer regions of cave is changed. This paper focuses on the environmental changes according to development of tourist resort in Gosu-cave. The result of this study can be found in the following facts: (1) As cave is opened lighting equipments set up for the purpose of helping inspection and coming in and out. (2) As the temperature rises in the coming in and out of tourist, this is caused to dry and peel off the topographes in cave. (3) The quality of water in cave is contaminated by the wastes, garbages and coins by tourists. (4) As Chungju - Dam has constructed, the linkages of the other tourist resort of Gosu - cave is improved. It is raised on the accessability of Gosu - cave. (5) As people has access to Gosu - cave, tourists increased more than the former times. Thus this phenomenon is contributed to the increasements of regional incomes and opportunity of regional employment.