Commelinaceae is a monocot family mainly distributed in tropical and temperate region. Several naturalized species were recorded in Taiwan these years. Recently we found a newly naturalized species-"Gibasis pellucida" (Martens & Galeotti) D.R. Hunt in Northern Taiwan. This species was native to Mexico, and introduced as ornamental plant in many countries. This is a newly naturalized species and genus for Flora of Taiwan. Line drawing, photos and distribution map were provided in this study. Finally, we revised naturalized species of Commelinaceae in Taiwan, the naturalization of them were related to ornamental activity, some species had set up large population already, especially the Tradescantia species. Thus we need pay more attention to these potentially invasive plants.