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[Objective] The purpose of this paper is to provide scientific basis for better protection of Ottelia acuminata and its sustainable utilization. [Method] Based on detailed investigation into its survival status and resources combining with the ways of land survey, analysis of life-type composition and regional components of vascular plants competing with the living space and nutrients of Ottelia acuminata was carried out in this paper. [Result] The resulLs showed that there were 27 families of vascular plants including 47 genera and 76 species in the distribution areas of Ottelia acuminata. Three types were classified according to their lifestyle and ecological types, 14 genera including 32 species were submerged plants, and 26 species of 20 genera and 18 species of 13 genera were aquatic and floating plants, respectively. From the view of composition of zone, 33 species were composed of 4 families with five or more categories each, belonging to dominant taxa of a-quatic vascular plants of Ottelia acuminata, taking up43.42% of total species. The geographical composition of the flora was complex and various. Families in this flora could be divided into 3 distribution types and 1 variant type, and there are 22 families in the world distribution type, 3 families in the tropical type and 2 families in temperate type. Genera could be classified into 9 distribution types and 2 variant types, and there were 20 genera in the world distribution type, 12 and 14 genera in the tropical and the temperate types, respectively. Species could be divided into 1 1 distribution types and 2 variant types, and there were 26 species in the world distribution type, 19 species in the tropical one and 24 species in the temperate one. Five species were endemic in China, but no endemic genera exist. [Conclusion] The geographical composition of genera and species reflects the nature of transition from tropical to temperate zones, the distribution of cos cosmopolitan, pantropics, old world tropics ami north temperate zone strongly influences the vascular flora of Ottelia acuminate population. [ABSTRACT FROM AUTHOR]