Abstract: Yilong Lake is a eutrophic plateau lake. The diversity of yeasts and the strains that produce extracellular enzymes and lipids were studied to understand the distribution of yeasts in Yilong Lake, and to explore the role of yeasts in the circulation of lake organic matter. In this study, the membrane filtration method was used to separate the yeast in the water samples of Yilong Lake. The 26S rRNA D1/D2 region sequence analysis and the method of combining morphological characteristics and physiological and biochemical indexes were used to identify the yeast, and the diversity of yeast was analyzed by BIO-DAP; The extracellular enzymatic activities of the isolated yeasts were tested by qualitative screening medium; Oil-producing strains were screened by combining Sudan Black-B staining and DNS spectrophotometric determination of residual sugar content. The results showed that 288 strains were isolated, and identified, which belonged to 26 genera and 41 species, including three potential new taxa: Rhodotorula kratochvilovae, Aureobasidium pullulans, Candida tetrigidarum with Filobasidium magnum being the dominant species. The Shannon diversity index (H′) and species richness of yeast in the western area of lake were lower than that in the eastern area. Most of the yeast isolated demonstrated at least one extracellular enzymatic activity (mainly lipase, pectinase and amylase activities); 20 strains with oil activity were obtained (mainly from Rhodotorula). It is concluded that the diversity of the yeasts from Yiling Lake is rich in diversity, and it is worth to develop and utilize.