Mycotoxin contamination is a major food safety issue worldwide, posing a serious threat to animal production performance and human health. Lactic acid bacteria are generally regarded as safe fermentation potential probiotics. They have the advantages of low toxicity, small pollution, strong specificity and high safety, and can reduce the contamination of microorganisms and mycotoxins. In this study, we compared the mycotoxin degradation capacity of 15 lactic acid bacteria strains from the rumen of Qinghai yak, through comprehensive analysis, we finally identified the strains as potential probiotics because they have a fast growth speed, strong acid production capacity (pH < 4.5), and they can grow normally in an environment with a pH of 3.5, bile salt concentration of 0.1%, and good self-agglutination and hydrophobicity. It was found that the fermentation group (Pediococcus acidilactici C2, Pediococcus acidilactici E28, Pediococcus pentosaceus A16 and Enterococcus lactis C16) could significantly reduce mycotoxin content, and both the nutritional and fermentation quality of the feed improved after 7 days of fermentation, meaning that the fermentation group can be used as a functional feed additive.