Abstract: Based on four bottom trawl surveys in the continental shelf of northern South China Sea from October 2006 to September 2007, species composition and community characteristics of catch were analyzed. The results showed that species of fishery resources were found the most in autumn and the least in winter. The number of fish species accounted for 79.42% of the total fishery resources. The relative biomass index and relative density index showed the same seasonal change, with the highest index in summer and the lowest in winter. The dominant species were Loligo duvaucelii, Polynemus sextarius, Leiognathus lineolatus and L.chinensis, whose IRI indexes were higher than 500. The main species were P.sextarius, Portunus sanguinolentus, Upeneus bensasi, Nemipterus bathybius, Acropoma hanedai, L.ruconius, L.edulis, Navodon xanthopterus, Champsodon atridorsalis, Acropoma hanedai, et al, whose IRI indexes were between 100 to 500. The number of species, the species richness index D, Shannon-Wiener index H′ and species evenness index J′ got the highest records in autumn 2006, and the lowest in winter and spring.