The studied section PM4 is located in the north of Taizhou City(32°34'N,119°56'E),southwestern Subei plain,the basal age of the section is 11.9 cal.ka B.P.The lithology of the section are composed of silt,silty clay and clay,and abundant organic residues were also found in the sediment.In total,82 samples were collected for palynological analysis at an interval of 4 cm in the 3.4 m-thick section.Based on the results of palynological analysis,we reconstructed 5 stages of vegetation change:(1) 11.90 ~8.80 cal.ka B.P.,subtropical evergreen and deciduous broadleaved forests developed as the zonal vegetation in the study area.They were dominated by Fagaceae trees (e.g.Cyclobalanopsis,Castanea,Quercus,Castanopsis).The climate was warm and humid.(2)8.80~7.40 cal.ka B.P.,herb taxa showed an expansion into the evergreen and deciduous broadleaved forests,as indicated by the increase of Chenopodaceae and Artemisia.The inferred climate condition turned to be relatively cold and dry.(3) 7.40 ~ 5.20 cal.ka B.P.,the pollen contents of Betula,Castanea,Pinus,Curpressaceae,Poaceae and Cyperaceae increased,while the Cyclobalanopsis,Quercus and Castanopsis,Chenopodiaceae and Asteraceae decreased.It is suggested that the precipitation would increase and the temperature decrease during this period.(4)5.20~1.08 cal ka B.P.,herb taxa expanded with a dramatic increase of Chenopodiaceae.The vegetation is salt marsh in the study area.(5) 1.08 ~0 cal.ka B.P,the contents of Chenopodiaceae and arboreal pollen decreased,due to the eastward movement of the coastline and possible human activity.The content variations of Chenopodiaceae,Artemisia,Poaceae and Cyperaceae can reflect the sea-level fluctuations by their implications for the vegetation response under the changing sea level.(1) During 5.20 ~4.55 cal.kaB.P,the contents of Chenopodiaceae (as a typical taxon in coastal saline vegetation) and Cyperaceae pollen increased,while those of Artemisia decreased,indicating that the sea level rose up.(2) During 4.55 ~4.25 cal.ka B.P.,Artemisia increased,while Chenopodiaceae and Cyperaceae sharply decreased,suggesting a relative fall of sea level.(3) From 4.25 cal.ka B.P.to 4.05 cal.ka B.P.,Chenopodiaceae and Cyperaceae sharply decreased,indicating that the sea level rose up again and more area was submerged.(4) During 4.05 ~3.00 cal.kaB.P.,local vegetation was mainly composed of Chenopodiaceae plants with a small amount of Artemisia,Poaceae and Cyperaceae,indicating that the sea level decreased.(5) During 3.00~1.85 cal.kaB.P.,Chenopodiaceae reduced along with the decrease of soil salinity,while Artemisia and Poaceae plants gradually increased,reflecting the further withdraw of sea level.The sea-level rising in the Subei plain during 4.25 ~4.05 cal.ka B.P.can be coincided with the worldwide 4.2 ka B.P. climatic event.The weakening of the East Asian monsoon,related strengthening of precipitation and large-scaled flood events in Eastern China could be responsible for the rise of the sea level in the Subei plain.