25 strains of yeasts were isolated from the natural fermented koumiss according to the colonial morphology and biological properties.The results of identification were as follows: 8 strains of Kluyveromyces marxianus,4 strains of Kluyveromyces lactis,1 strain of Saccharomyces cerevisiae,and 1 strain of Galactomyces geotrichum,the rest can't be deduced.25 stain of yeasts were identified by 5.8S rDNA sequencing,and strain 1,2,18,25,27,and 28 were further identified by phylogenetic tree analysis.The results of identification were as follows: 10 strains of Kazachstania unispora,8 strains of Kluyveromyces marxianus,4 strains of Kluyveromyces lactis,1 strain of Saccharomyces cerevisiae,and 1 strains of Geotrichum candidum.Strain 27 might be a new species.The identification results were important for us to increase the awareness and usage of traditional fermented dairy products in yeast resources.