Abstract: Xylo-oligosaccharide is a kind of functional oligosaccharide with higher additional value which is able to promote the proliferation of intestinal beneficial bacteria, suppress the growth of harmful bacteria, and regulate the intestinal microflora balance. Due to its smaller addition quantity and superior stability, xylo-oligosaccharide is widely used in the fields of feeding stuffs, food and medicine industry. The characteristics and application status in food industry and ruminate animal production of xylo-oligosaccharide is introduced, with emphasis on the research progress on its protective effect on calf diarrhea, in hoping to provide references for the scientific use of xylo-oligosaccharide in animal husbandry production.