According to the abundance and assemblage of diatom and content with certain parameters of pigments, and the analysis of spore-pollen and total organic carbon from rhe sediments of the Core GS₁ of Gucheng Lake, Jiangsu Province, this paper has discussed the palaeoclimat-ic and palaeoenvironmental evolution in the Gucheng Lake region from Late Glacial period to the middle of Holocene in detail, including the formation of Gucheng Lake and monsoon rainfall at 14ka B.P.Allerod warming period with a less effective moisture, cold and humid Younger Dryas event, a number of low temperature periocis at 8.5, 7.8 and 6.5 ka B.P.in warm and wet climate background of early-mid Holocene.In general, tFie palaeolimnologic history of Gucheng lake is macroscopically controlled by monsoon climate cycle resulted from orbital forcing, bur i.s complicated by the intervention of marine transgression and abrupt climate event-In the meantime, rhe authors also try to contribute rhe combining of diatom and pigment to evaluate the lake paleoprimary productivity, and to distinguish the human activities in lake records.The results suggevst that diatom along with pigments is not only an effective indicator for lake production, but may also be used to diagnose the texture change in algae plant community.This paper also deals with the strata characteristics and background when the marine diatom of early Holocene appeared, and makes a comparison with that from Taihu Lake.No doubt that this phenomena will be very important to get deeper insight into the palaeogeo-graphy environment of rhe Yangtze River Delta region.