Forty-three samples of kurut, a kind of traditional naturally-fermented yak milk, were collected in Qinghai, China. One hundred and forty-eight lactic acid bacterial (LAB) strains were isolated and identified from the kurut samples according to phenotypic characterization and 16S rRNA gene sequence analysis. Among them, 52 isolates belonged to the Lactobacillus strains. Ninety-six isolates were resolved to coccoid LAB. The results showed that these isolates belonged to five genera and thirteen different species and subspecies. Moreover, Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus were the predominant population in these samples. This paper systematically studied the composition of LAB in kurut, which may provide raw data for further study involving probiotics strain selection and starter culture design for industrialization production of traditional fermented milk in the future.