During the fifth Chinese National Arctic Research Expedition in 2012, two strains of brown seaweeds were collected from the Bering Sea and Greenland Sea, respectively. Their morphological characteristics have been described, and taxonomic status has been studied based on DNA barcoding sequences. Both morphological characteristics, and phylogenetic relationships based on ITS2 sequences, proved that strain AE5-8 from the Bering Sea belonged to Agarum clathratum subsp. clathratum. This species can be found from Hokkaido, Japan, via Alaska to the west and east coasts of North America. The Greenland Sea alga AE5-12 belonged to Ascophyllum nodosum based on the phylogenetic trees of DNA barcoding sequences ITS and COX1. A. nodosum is a dominant fucoid seaweed occurring throughout the North Atlantic. No North Pacific representatives of this species have been reported.