The study investigated the community of Begonia jinyunensis and its associated species in Jinyun Mountain National Nature Reserve. With the sample plot as onedimension resource states and with the importance values as the resource state descriptor of the niche, the niche characteristics of B. jinyunensis populations based on the formulae by Levins and Hurlbert for niche breadth and Piankas niche overlap were measured, which clarified the relationship between the use of resources and competition among the species of the community, providing a basis for the protection of B. jinyunensis. The results showed that: (1) the niche breadths of Levins and Hurlbert for B. jinyunensis in the community were the highest, 6.744 40 and 0.717 80 respectively,indicating that its ability of using environmental resources was strong and the ecological adaptation range was also large. (2) The niche breadths (Ba) over 0.3 for its associated species were Elatostema rupestre, Arachniodes rhomboidea and Polystichum tsussimense, 0.460 00, 0.417 04 and 0.301 60 respectively, indicating that the three major associated species of B. jinyunensis had stronger competitiveness in the community. (3) Among 20 species, the highest niche overlap with B. jinyunensis was E. rupestre, 0.671 4, showing they both had similar environmental requirements. When resources were insufficient, there may be fierce competition between them. And 12 species overlapped less than 0.5, occupying 60%. The niche overlaps of most species with B. jinyunensis were low, which showed the demand of resources varied and the similarity of environmental adaptability was low among species, indicating the interspecific competition in the community was not intense. According to the research, the niche breadth of B. jinyunensis was large, the habitat was suitable for its survival and the competition among species was not intense. The niche factor currently was not the main reason causing it to be endangered. The main reason for the small population of B. jinyunensis and the islandlike distribution may be its vandalized habitat.