Demersal trawl collections of fishes were made in 4 seasons (May,1983 to February, 1984) at 50 stations distributed between 40 and 200-m isobeths on the continental shelf.Based on presence-absence data of 125 fishes recorded at least 3 times in thg 200 hauls，the spacies are clustered by group--average rlassi.fi-cation of an association matrix of Jaccard's coefficient of community. Eight co-occurrent species groups are derived. The dominant species group is further dig-ided into 4 subgroups.To illustrate the environmental requirements of fishes,the abundances of each species are arranged along gradients of depth, bottom layer temperature，salinity and sediment types. The gradient analysis shows that the clustering pracedure groups the fishes that have similar reactions to properties of the environment. Thus, the groupings are used to sun}zuarire erwironmental requirements and distribution ranges of fishes. A subgroup of indifferent species spreads and dominants throughout the shelf area. Other species groups and sub-groups are associated with certain environmental conditians and their distributions zone with depth. The dramatic increase in depth and decrease of temperature. on the shelf edge coincide with the distributiona.l limits of most shelf fishes. The abundane.es of all species groups decrease or disappear on the shelf edge, but the ahundances of the species group characterizing shelf edge and slop environments increase w ith depth. The species groupings as inverse analysis of community patterns indicate that due to environmental changes, the assemblages of fishes vary with depth and faunal changes a.re rapid on the shelf edge region. This conforms the results of previous normal analysis of the community.