This research investigated the change of weeds community by winter-flooded that conducted at shore of Inba Lake, and compared to the different of weeds community in dry-rice-field. As a result, we could confirm empathic difference between winter-flooded rice field and dry-rice-field. In regard to species number per year, winter-flooded rice field intended to be fewer in comparison to dry-rice field. In regard to the plants volume, although winter-flooded rice field were higher than dry-rice field at summer, otherwise dry-rice field were high. In winter-flooded rice field, plant volume of Monochoria vaginalis which was dominant at summer and autumn extremely increased, and in winter, plant volume of Alopecurus aequalis which was dominant species in pre-winter flooded extremely decreased.