The invention relates to the technical field of medicines, and particularly relates to an arformoterol tartrate powder inhalation capsule and a preparation method thereof. The arformoterol tartrate powder inhalation capsule provided by the invention comprises a capsule content and a capsule shell, wherein the capsule content is mainly prepared from arformoterol tartrate and a lactose monohydrate;the capsule shell is mainly prepared from hydroxypropyl methyl cellulose, chitosan oligosaccharide, tamarind gum, sorbitol and water. The arformoterol tartrate powder inhalation capsule provided by the invention has the advantages that the particulate mobility is good, the hygroscopicity is low, and the content uniformity and effective-site deposit quantity are high, and meets the Quality Standardof Formoterol Fumarate in the European Pharmacopoeia 7.0 and the relevant requirements of Powder Aerosol in Appendix IL of Volume II of Pharmacopoeia of The People's Republic of China, 2010. Moreover, the arformoterol tartrate powder inhalation capsule prepared by the preparation method also has the advantages of high safety and high stability, and the large-scale popularization and application are more facilitated.