Ottelia acuminata is listed in Yunnan Province Protected Plants (Class III) as a rare and endangered plant species. Ottelia acuminata community used to be a dominant community type in Yunnan's plateau lakes, but it is only found in a limited number of lakes nowadays with its observable changing characteristics. In the present study, species composition and distribution patterns of the community in Lake Jianhu were studied, with plot method and dispersal coefficient method in order to understand the development trend of the population, the relationship between its distribution pattern and environmental factors, and to provide some scientific basis for the protection of Ottelia acuminata and plateau lakes. The results showed that the community was composed of 18 species belonging to 12 families and 14 genera, with submerged type, free-floating type, floating-leaved type and hygrophyte as four major life forms. The distribution pattern of Ottelia acuminata and Potamogeton malaianus was clumpy, while other species were randomly distributed. The aggregation intensity of Ottelia acuminata was the highest among all species, which was close to the maximum clump distribution. Ex-situ conservation, basin maintenance and habitat management are some promising approaches to effectively slow down lake swamping process and conserve Ottelia acuminata community.