AbstractSpecies diversity, quantity, distribution and community of macrobenthos are analyzed in this paper. The materials were collected from 16 stations in the Chukchi Sea and Bering Sea in Summer 1999. For quantitative analysis, samples were collected by a 30 cm×30 cm box sampler. There were in all 92 families and 164 species, of which Polychaeta comprised 62 species, Mollusca 42, Crustacea 37, Echinodermata 14 and other groups 9 species. Polychaeta, Mollusca and Crustacea occupy 88.41% of all species. Cossurella sp., Tharyx sp., Maldane sarai, Nephtys caeca, Phascolion sp., Ennucula tenuis, Nuculana pernula pernuloides, Clinocardium (Ciliatocardium) ciliatum, Asthenothaerus sp., Eudorella pacifica, Lepidepecreum sp., Harpiniopsis sp., Byblis japonicus, and Ophiura sarsii were dominant species and key species. The average biomass was 111.83 g/m2,and individual density was 2538 inds./m2 in Chukchi Sea and Bering Sea.Five macrobenthic commumities from Chukchi Sea and Bering Sea are recorded in this paper. They are Community Ⅰ. Scalibregma inflatum-Polycheira rufescens-Stegophiura nodosa, Ⅱ. Cossurella sp. -Ennucula tenuis-Lepidepecreum sp., Ⅲ. Maldane sarai-Hippomedon gorbunovi Ophiura sarsii, Ⅳ. Nephtys sp. -Ennucula tenuis -Byblis japonicus-Golfingica sp., and the Community of the Bering Sea, Lumbrineris fragilis-Asthenothaerus sp. -Eudorella pacifica-Phascolion sp. Commumity of the Bering Sea and Communities Ⅰ and Ⅱ in Chukchi Sea are relatively stable, but disturbance characterizes Communities Ⅲ and Ⅳ in the Chukchi Sea.