This study is to examine the environmental characteristics of subpopulations of Ilex crenata var. microphyllla Max. distributed in the east-west slopes of Mt. Halla National Park based on analyzing the factors of environment, vegetation and soil. The result of the TWINSAPN analysis conducted on 56 study plots between the altitudes of 500 m and 1600 m of east-west slopes of Mt. Halla National Park can be divided into five communities-Prunus maximowiczii Rupr., Manshurian fullmoon Maple, Carpinus tschonoskii Max., Daphniphyllum macropodum Miq., Quercus serrata Thunb. ex Murray and Pinus thunbergil Parl. Among these communities, the plot with high importance percentage of the subpopulation of Ilex crenata var. microphyllla Max., is the Carpinus tschonoskii Max.-Daphniphyllum macropodum Miq. included in the altitude of 600m~1200m radius. The dominant species of the upper shrub layer was Carpinus tschonoskii Max.(I.P.: 29.82%) while the dominant species of the canopy layer was Daphniphyllum macropodum Miq.(I.P.: 26.76%). For the understory layer the dominant species was Ilex crenata var. microphyllla Max.. Species diversity index was on the low end with 0.7424, indicating the stably formed climax community of Carpinus tschonoskii Max.. The analysis of soil properties showed high concentrations of organic matters, available phosphate and Ca, Mg, the high importance percentage of the of Ilex crenata var. microphyllla Max. is found in altitude of 600m~800m on the eastern slope and the altitude of 800m~1,000m radius on the west slope. This region is included in the southern part of the cold/hot forest zone, its high importance percentage of Carpinus tschonoskii Max. and low in the species diversity index of 0.7424, and has formed stable climax community of Carpinus tschonoskii Max. in Mt. Halla.