The invention discloses a characteristic marker of a milk exosome and a method for identifying the milk exosome. The marker is an N-linked sugar chain; and the molecular weight and the structural formula of the N-linked sugar chain are 1599.5656 (Man)5(Gal)1(GlcNAc)3 and 2192.8088 (Fuc)1(Man)3(Gal)2(GlcNAc)6. According to the invention, two reliable milk exosome characteristic N-linked carbohydrate chain structures are screened to serve as the marker of the milk exosome; the exosome can be simply, conveniently and quickly identified by utilizing the two characteristic N-linked carbohydrate chains; and the method has practical significance in research on clinical targeted drug loading.