Based on trawl survey data from May and October of 2006 in Yellow Sea off the coast of Shandong, China (35º00′-38º00′N, 120º30′-124º00′E), fish composition, dominant species, fish community diversity and size spectra were studied. A total of 61 species were collected, all of them were Osteichthyes species, belonging to 57 genera, 37 families and 13 orders. The most species-rich orders were Perciformes (27 species), Clupeiformes (8 species) and Scorpaendiformes (7 species). There were 7 fish groups according to an analysis of feeding habit: planktivores, planktivores/benthivores, benthivores, benthivores/piscivores, piscivores, omnivores, detritivores. Planktivores accounted for 82.5% of the total catch. There were 3 dominant species (Ammodytes personatus, Engraulis japonicus and Pholis fangi) in spring and 5 dominant species (Engraulis japonicus, Sardinella zunasi, Ammodytes personatus, Larimichthys polyactis and Thryssa kammalensis) in autumn according to analysis of Hill’s diversity; most of these were small-sized species. The highest diversity was found in the coastal waters (particularly in Qingdao and southern of Rushan waters), fish diversity decreased with increasing of water depth, and no significant differences were found between spring and autumn diversity indices. Biomass was negatively correlated with overall diversity and functional group diversity. The slope of size spectra was less than -0.2 both in spring and autumn, and the intercepts were both bigger than 10. When comparing 2006 data to 1985 and 2000 data, slope decreased, and intercept increased. These results might be attributed to the increased dominance of small-sized species in the total catch. Compared with historical data, fish resources in Yellow Sea off the coast of Shandong are obviously declining, with community diversity decreasing and proportion of small-sized individual increasing.