Abstract: Trawling shrimp is a main operating method of capture fishery off the north of South China Sea. Estuary of Pearl River in the north South China Sea is one of very good shrimp trawl fishing ground in the waters off Guangdong. On the basis of data obtained in the shrimp trawl ecological survey for Tonggu Waterway of Pearl River Estuary, we analyzed composition of by-catch for the fishery in this paper. Results showed that catches of shrimping beam trawl have many species in Estuary of Pearl River in the north South China Sea. The species in catches were dominated by fishes and crustaceans; Composition of by-catch changed in the different months; Percentage of by-catch was relatively high, the ratio of shrimp to by-catch is 1:10~1:19; Most fish species of by-catch were commercially undersized species, with damage to juvenile fish resources. We suggest that fishery administration should emphases on research into the by-catch problem.