Aso-region in Kumamoto Prefecture has a magnificent grass landscape. Because of volcanic conditions and cool climate, it has been the area that grassland tended to be formed. In addition, some artificial effects such as control burning, grazing and grass harvesting have been kept this state of natural succession. This type of grassland is called as “semi-natural grassland” and is an important area for biodiversity conservation in Japan. Although this landscape is a cultural landscape that it has been formed traditional land use derived by livelihood of local people. However, it has been changed gradually by social and economical impacts and large scale land changing. In this study, initially we studied characteristics of cultural landscape and changes of land use in the area. After that, we investigated vegetation structure in grasslands managed by common users and in tree plantation governed by Aso-city. In addition, we got the information of managing history of both grassland and tree plantation by using “grassland card” and “forest registration”. In the result, their grasslands are similar on dominate species with few varieties. However, it can be founds the more species biodiversity in traditionally managed grasslands than in grasslands have histories of an alteration.