Objectives The effects of feeding white yak with micro-storage hay for fattening in high-altitude areas were studied to guide breeding farms (households) to scientifically and reasonably utilize hay to achieve the goal of cost decreasing and benefit increasing. Methods 36 healthy Tianzhu white yaks around 3 years old with a body weight of about 285 kg were randomly divided into the Group Ⅰ(control group), Group Ⅱ, and Group Ⅲ, with 12 yaks in each group. The feed was mixed according to the ratio of concentrated feed to coarse feed (4∶6). Under the same daily feeding of concentrated feed, group I was fed with dry hay, Group Ⅱwas with fed (50% dry hay+50% micro-storage dry hay), and group III was fed with micro-storage dry hay. The growth performance, slaughter performance, and economic benefits of white yaks were measured separately after 90 days of feeding and fattening inside house. Results The average daily weight gain in Group Ⅲ increased by 0.05 and 0.09 kg, compared to that in Group Ⅱ and the Group Ⅰ, respectively. The feed to weight ratio in Group Ⅰ, Group Ⅱ, and Group Ⅲ was 11.03∶1, 10.97∶1, and 10.65∶1, respectively. There were significant differences between the Group Ⅲ and Group Ⅰ in terms of growth performance.There were no significant differences among the three groups in the rate of slaughter, rate of net meat production, rate of carcass meat production and average eye muscle area. The total feed cost and the average benefits in the experimental group Ⅲ decreased by 0.33 and 0.25 yuan, and increased by 0.40 and 0.46 yuan compared to that in the experimental group Ⅱ and the experimental I with an average increase of 1 kg body weight. Conclusions Using micro-storage hay to feed white yaks for fattening in high-altitude areas can effectively improve the utilization of hay, reduce the loss of hay, and enhance the efficiency of fattening white yaks.