Coastal wetland is an interaction interface among terrestrial,ocean and atmosphere,and is sensitive to the responses of global change and anthropogenic impacts,and the sedimentary records in coastal wetland can be used to reveal the information of local environmental change and anthropogenic impacts.Analyzed results for the sediment core named QA,obtained by drilling in coastal wetland of west Qi'ao Island(QAI),indicate that the surrounding area of the QAI was estuarine environment during the mid-Holocene,and the sea-bed began to experience a slight accumulation.However,due to the extreme cold climate influence near 4 200aBP,the sediment showed a coarsen trend.Since 2 500aBP,the sedimentary environment near the QAI was stable except during the Little Ice Age(LIA).Based on the radioisotope dating(14 C and 210 Pb)and the inferring conclusions according to the sedimentary structure of the core and sediment grain size variation,the mean sedimentation rate since mid-Holocene was 0.29cm/a,and the sedimentation rates in the stages of 4 160-2 500aBP,2 500aBP-1488AD,1488-1893AD,1893-1986AD,and since 1990AD were 0.17cm/a,0.23cm/a,0.35cm/a,1.37cm/a and 5.94cm/a,respectively.The increase of sedimentation rate indicated the variation of sedimentary facies and sedimentaryenvironment during the formation and evolution of the Zhujiang River Delta.During 1986-1990,the construction of the seawall disturbed the sedimentary process immensely and induced a 112 cm sediment layer occurred near the seawall,and the sedimentation rate increased evidently after the construction of seawall.The depth-distribution of total organic carbon(TOC),total nitrogen(TN)and C/N ratio indicated that the organic carbon was composed mainly by marine source during 4 160-2 500aBP because the sedimentary environment near the QAI was influenced by marine environment mainly;since 2 500aBP,the contents of TOC and TN increased as well as the variation of the C/N ratio revealed that the organic carbon mainly came from terrestrial input,although the contribution of marine source increased slightly during the LIA;however,the contribution of terrestrial organic carbon increased remarkably in recent one hundred years due to the intense anthropogenic impacts in the catchment area of the Zhujiang River and surrounding area of the estuary.