The aim of this study was to investigate the effects of EM microbial fungicide with cow and sheep manure on the yield，quality of oats and soil quality at high altitude.Using ‘Qinghai sweet oats’ as the material，the effect of different doses of EM microbial agents(EM1，EM2，EM3，EM4，EM5)with cow and sheep manure was compared and no fertilization(CK)was used as control.During the growing season(May-October)，the effects of treatments on growth and development，yield quality，soil nutrients and enzyme activities of oats were observed.The results showed that the application of EM fungicides significantly promoted the growth of oats，especially in plant height，total root length，leaf area and leaf fresh mass，with the highest plant height in EM4 treatment，which increased by 20.11%，compared with CK.For photosynthesis，additional application of EM fungicides increased oat SPAD value，photosynthetic rate，transpiration rate，stomatal conductance and intracellular CO₂ concentration，with the net photosynthetic rate of EM3 and EM4 treatments exceeding 13 μmol/(m2·s)，which was increased by 34.38% and 33.57%，respectively，compared with CK. Nutritional quality analysis showed that the crude protein and soluble sugar contents of EM3 treatment were 7.13% and 10.65%，respectively，which were significantly higher than that of CK by 38.71% and 32.46%，respectively，and the total digestible nutrient contents were above 60%，which were significantly better than that of CK.In terms of forage yield，the EM3 treatment had the highest fresh and hay yields，which were 28492.00 kg/hm² and 10928.80 kg/hm²，which increased by 28.57% and 54.36%，respectively，compared with CK.As for soil quality，soil organic carbon and total nitrogen content increased significantly after the application of EM fungicides，and the EM3 treatment group had the highest total nitrogen content，which increased by 18.23%，compared with CK，while soil conductivity and pH decreased.Soil BG and NAG enzyme activities peaked in EM3 treatment，which significantly increased by 60.31% and 70.68%，respectively.The comprehensive evaluation analysis of the affiliation function showed that the improvement effects of each treatment group on oat growth and soil quality were in the order of EM3>EM4>EM5>EM2>EM1>CK，indicating that EM3 treatment had the best effect.Therefore，this study showed that the combination of 15.00 kg EM microbial agent with 18000 kg/hm² of cow and sheep manure applied at high altitude demonstrated the best results，which significantly promoted the growth and development of oats，improved their nutritional quality，and effectively improved soil nutrients and enzyme activities.It was recommended to promote this fertilization program at high altitude to enhance oat yield and soil health and to promote green and sustainable production of oat forage at high altitude.