The invention relates to the technical field of probiotics, particularly to sugar-free probiotics powder and a preparation method thereof. The sugar-free probiotics powder comprises water-soluble dietary fibers, fructo-oligosaccharides, xylooligosaccharides, stachyose, Lactobacillus acidophilus powder, Lactobacillus plantarum powder, Lactobacillus rhamnosus powder, Lactobacillus casei powder, Bifidobacterium bifidum powder, Bifidobacterium breve powder and Bifidobacterium lactis powder. Compared with the prior art, the sugar-free probiotics powder and the preparation method thereof have the advantages that a formula and the preparation method of the probiotics powder are designed, the probiotics powder has the sugar-free characteristic, a user is prevented from ingesting excessive sugar while supplemented with a large quantity of probiotics prebiotics, on one hand, the obesity probability is reduced, and on the other hand, special groups suffering from diabetes and the like can also take the powder. The powder has the characteristics of good solubility, good taste, natural raw material, scientific formula and balanced nutrition.