In Japan, Coreopsis lanceolata has been invading riverbed vegetation and is designated as an invasive alien species. A study regarding its occurrence and the vegetation transition in the riverbed of Kiso River was conducted. Comparing the vegetation maps of 1979, 1996 and 2006 revealed that over time, the area of the wet grassland had decreased. However, the forest area and bamboo/dwarf bamboo community had increased. Contrastingly, the area of the dry grassland tends to change little and is sustained. C. lanceolata occurred in 70% of the area of the dry grassland and 50% of the area of shrubs in 2006. C. lanceolata occurred frequently in the Artemisia capillaris-Anaphalis margaritacea subsp. yedoensis community and Zoysia japonica-Potentilla chinensis community in 2006. This study reports regarding some types of the dry grassland including the communities with the specific native plants that was sustained for a long time and is invaded easily by C. lanceolata.