We monitored the butterfly community dynamics from March to October for the three years (2002, 2003, 2004). The study areas were consisted of the five sectors with pine forest (Pinus rigida) and mixed oak forests at Mt. Midong in Chungwongun, Chungchungbukdo, Korea. We found that the total numbers of butterfly species were 59 species and the total individuals were 1,513. There was no change the number of species (44 species) during the study period but the composition of species and the number of individuals were different such as 414, 561, and 538, respectively. The most abundant species were Minois dryas (25%) in 2002, Polygonia c-aureum (24%) in 2003, and P. c-aureum (22%) in 2004. On the contrary, the number of singleton species was 20 species in 2002, 15 species in 2003, and 15 species in 2004. We found that there was the seasonal difference in species composition of butterfly community. The species diversity of butterfly community was the highest at sector 4 and sector 5 and lowest at sector 2. Main reason of the butterfly dynamics was strongly supposed to the human activity. We could suggest that the butterfly monitoring study must be a good way to measure the change of butterfly habitats including anthropogenic activity and the natural disturbances.