According to the data collected in 4 surveys of the North Yellow Sea(36.95°N~39.66°N, 120.95°E~124.02°E)during aperiod lasting from 2006 and 2007,the species composition,abundance variation,distribution pattern and the relation between Thaliacea and environment were analyzed.A total of 4species were recorded,3in summer and 1in spring,1in autumn,and no Thaliacea species was recorded in winter.Salpafusiformis was an important species in surveyed area,which was 2.5and 5.2ind/m~3 in average in spring and summer,respectively.Salpafusiformis mainly distributed in the Yellow Sea Bottom Cold Water area,and the regional distribution in summer was more widely ranged than that in spring. Cold-water species Cyclosalpa bakeri was only recorded in summer in the Yellow Sea Bottom Cold Water area,with a low average abundance 0.1 ind/m~3.Warm-water species Doliolum denticulatum widely distributed in the North Yellow Sea in autumn,and the average abundance was 34.4 ind/m~3.This was the first typical warm-water species recorded as a dominant species in the North Yellow Sea.The appearance of the typical warm-water species with great abundance in the North Yellow Sea might signal the temperate response of marine ecosystem to global warming,and more observations and studies on this rare phenomenon are highly appreciated.