Abstract: The floristic features and geographical distribution of aquatic vascular plants were summarized in Zhejiang Province based on 15-year investigations. There were 150 species belonging to 78 genera and 42 families in the province. Eleven areal types were classified from these genera, in which the highest proportion was cosmopolitan, followed by the tropical and then temperate. The species were classified into 13 areal types, in which East Asia element was the dominant. The proportion of temperate elements was much higher than the tropical, representing obviously the feature of Sino-Japan flora. The horizontal zonality and the vertical zonality of the aquatic plant distribution in Zhejiang Province were analysed. The distribution is not only correlated with climate zone, but is much more correlated with the Pattern of habitats. Finally, we proposed a list of threatened species of aquatic plants in Zhejiang Province, with a discussion on their threatened degrees.