The occurrence and abundance of different ostracod species are sensitive to changes in environmental factors,especially to the temperature and the salinity7 of water bodies.Thus,the ostracods can be used as a scale rough measure of temperature and salinity in the analysis and reconstruction of paleoenvironments.In order to interpret the climate-change data using the ecological characteristics of the ostracods from the drill cores in Lake Qinghai,the distribution of Recent ostracods was studied in Lake Qinghai area.A total of 34 species belonging to the Ostracoda class of Crustacea were collected from different bodies of water in the Lake Qinghai area,and the ecological information for Recent ostracod species was studied.Among these 34 species,Cypris pubera,Eucypris dulcifons,Ilyocypris sp.1,Ilyocypris sp.2,Fabaeformiscandona caudata,Fabaejormiscandona byalina,Plerpetocypris reptans,Prionocypris gansenensis,Potamocypris villosa,Potamocypris smaragdina,Paralimnocythere compressa and Subulacypris sp.were first reported by us in the Lake Qinghai area.Some of the species identified exhibited cosmopolitan distributions,at least in the Holarctic region,but P.gansenensis and Ilyocypris ecbinata appeared to be restricted to the cold regions in northwestern China.The ecological significance of the primary ostracod species in the Lake Qinghai area was described according to the observations made during our time in the field and according to data from a number of reports.Our results indicate that the species diversity and abundance of ostracods may be related to water salinity in the Lake Qinghai area.The ecological information for ostracods can be used to distinguish different water environments and types based on the characteristics of one species or of an assemblage of several species. The occurrence and abundance of different ostracod species are sensitive to changes in environmental factors, especially to the temperature and the salinity 7 of water bodies. Thus, the ostracods can be used as a scale rough measure of temperature and salinity in the analysis and reconstruction of paleoenvironments .In order to interpret the climate-change data using the ecological characteristics of the ostracods from the drill cores in Lake Qinghai, the distribution of Recent ostracods was studied in Lake Qinghai area. A total of 34 species belonging to the Ostracoda class of Crustacea were collected from different bodies of water in the Lake Qinghai area, and the ecological information for Recent ostracod species was studied. Among these 34 species, Cypris pubera, Eucypris dulcifons, Ilyocypris sp.1, Ilyocypris sp.2, Fabaeformiscandona caudata, Fabaejormiscandona byalina, Plerpetocypris reptans, Prionocypris gansenensis, Potamocypris villosa, Potamocypris smaragdina, Paralimnocythere compressa and Subu lacypris sp.were first reported by us in the Lake Qinghai area. Home of the species identified as cosmopolitan distributions, at least in the Holarctic region, but P. ggansenensis and Ilyocypris ecbinata, to be restricted to the cold regions in northwestern China. ecological significance of the primary ostracod species in the Lake Qinghai area was described according to the observations made during our time in the field and according to data from a number of reports.Our results indicate that the species diversity and abundance of ostracods may be related to water salinity in the Lake Qinghai area.The ecological information for ostracods can be used to distinguish different water environments and types based on the characteristics of one species or of an assemblage of several species.