Based on two bottom trawl surveys conducted in autumn of 2000 and spring of 2001 in the Yellow Sea, functional groups at high trophic levels in the Yellow Sea ecosystem and its three sub-ecoregions, i.e. the Yellow Sea cold water mass region, the Yellow Sea coastal water region and the southern Yellow Sea region, were analyzed. Species picked out for analysis covered more than 90% of the total catch in biomass, which were divided into six functional groups according to their feeding habits, planktivors, benthivores, piscivores, shrimp predators, generalist predators and shrimp/fish predators in order of biomass. The trophic levels of these functional groups were estimated as 3.22-3.35, 3.30-3.46, 4.04-450, 3.80-4.00, 3.38-3.79 and 4.01, respectively. In the Yellow Sea ecosystem, there were two major functional groups, planktivors and benthivores, which accounted for 79.6% of total biomass, and 13 major species, small yellow croaker (Pseudosciaena polyactis), anchovy (Engraulis japonicus), Parapenaeopsis tenella, silver pomfret (Pampus argenteus), Ovalipes punctatus, largehead hairtail (Trichiurus haumela), croaker (Collichthys niveatus), half-fin anchovy (Setipinna taty), Bombay duck (Harpodon nehereus), Charybdis bimaculata, sea snail (Liparis tanakae), Portunus trituberculatus and long-tailed anchovy (Coilia mystus), which accounted for 70.6% of total biomass. The average trophic level of the populations at high trophic levels varied slightly between the three sub-ecoregions in spring, but greatly in autumn, as a reflection of the feeding habits of the migratory spawning and foraging populations. Planktivors formed the major functional group in the sub-ecoregion of the Yellow Sea Cold Water Mass. The average trophic level of the populations at high trophic levels in this region was quite steady during a year, while that in both the sub-ecoregions of the Yellow Sea coastal water and the southern Yellow Sea changed much seasonally, higher in autumn than in spring. It indicates that the Yellow Sea cold water mass bring about a typical sub-ecoregion with more stable environment than others regions in the Yellow Sea ecosystem.