Samples of demersal fishes were taken with trawlnet seasonally for a 2-year period (1982 to 1984) on the continental shelf, ranging in depth from 40 to 260m. Fifty-eight stations are grouped into 5 major clusters using complementary classification, and mufti-diwensional scaling ordination techniques. These are both based on root-rant transformed mean biomass data with the Bray-Gurtis measure of similarity. Faunal changes over 40, 100, and 200m isobeths separate regions of relative faunal homogeneity. One faunal assemblage can be identified in the area to the west of the Taiwan Bank, a second along the 40ui isobeths, a third between the 40 and 100m isobeths, a fourth between the 100 and 20flzn isobeths, and a fifth an the continental shelf edge.Each assemblage was charaeterized by faunal composition，catch rates, species diversity and dominant species, as well as the environmental conditions the assemblage adapts to. Faunal changes are probably clue to the gradients of temperature, salinity and depth, as well as differences in sediment type. That the fish fauna are zoned with depth may be established on the shelf. The zonatian reflects joint response to environniental factors, The dramatic faunal changes at the shelf edge are mainly induced by rapid increase in depth and decline in bottom temperature, and the 200m isobeth may be suggested as the boundary of the shelf fauna. The community structure was considerably changed by fishing, especially in shallower zones. There might be potential for changing the patterns of fishing by area regulation to obtain fine turning of the community.