Abstract: To clarify the basic situation of resource and fauna of butterflies in the southeastern edge of Mu Us sandy land and provide basic data for the conservation and utilization of butterfly resources, butterflies in this area were captured and identified from June to September in 2013, 2014 and 2015. The results showed that there were 52 species belonging to 38 genera in 5 families in the southeastern edge of Mu Us sandy land, including 3 species belonging to 1 genus in Papilionidae, 4 species belonging to 4 genera in Hesperiidae, 10 species belonging to 6 genera in Pieridae, 21 species belonging to 14 genera in Nymphalidae and 14 species belonging to 13 genera in Lycaenidae. Butterfly resources in the southeastern edge of Mu Us sandy land were mainly Lycaenidae and Nymphalidae, and the dominant species were Colias erate, Pieris rapae, Coenonympha amaryllis, Aricia mandschurica and Everes argiades. Fauna distribution showed that the major species in the southeastern edge of Mu Us Sandy Land were Palaearctic species, with 31 species accounting for 59.61% of the total species, followed by widespread species, with 20 species accounting for 38.47% of the total species. The southeastern edge of Mu Us sandy land belonged to transition zone for butterfly fauna from Loess Plateau to desert and semi desert area.