Xinfengjiang Reservoir is a large deep oligotrophic reservoir located in Guangdong Province, South China.In order to understand the structure of zooplankton community in this oligotrophic water body, rotifers, cladoc-erans and copepods, were investigated in 2002 and 2003.The zooplankton species were mainly composed of eury-thermal ones, and only a few thermophil ones were also found.The zoopkankton were dominated by copepods, in which nauplii and copepodites contributed more than 72.5% to the total abundance of copepods.The dominant species were Phyllodiaptomus tunguidus, Mesocyclops thermocyclopoides and Tropocyclops parvu.Cladocerans were mainly composed of Bosmina longirostris, Diaphanosoma brachyurum and Ceriodaphnia cornuta.Bosmina longirostris had the highest abundance in the cladocerans, and its dominance was probably related to its adaption to oligotrophic status and being free of invertebrate predation.Rotifer's dominant species were Keratella cochlearis and Chromogaster sp..The body lengths of zooplankton in the reservoir ranged from 50μm to 1400μm.The largest dominant species was Phyllodiaptomus tunguidus with an average length of 1190μm.Chromogaster sp.was the smallest dominant one, and its average length was 80μm December, perhaps due to the heavy predation by ice-fish (NeosaLanx taihuensis Chen), the abundance and biomass of Phyllodiaptomus tunguidus were lower than in three other sampling periods.The dominance of Phyllodiaptomus tunguidus in the reservoir was probably related to its low threshold food concentration and efficient filtering mode in comparison with Daphnia hyalina.In viewpoint of the species composition, the zooplankton in Xinfengjiang Reservorir has a typical identification of oligotrophic water bodies.