Abstract: In this paper,we studied the distribution characteristics of lignin in three sediment cores Ra7,Za6 and Zb7 from the mud area off Hangzhou bay.The organic sources were discussed to reveal the influence of human activities on the change of regional sedimentary environment in a short time scale.The results showed that the organic matter in the study area was predominantly from marine sources relative to terrestrial.The lignin contents normalized to organic carbon (Λ8) were (1.06±0.29)×10^-2,(0.89±0.33)×10^-2 and (0.99±0.20)×10^-2 in Ra7,Za6 and Zb7,respectively.Overall,the lignin content was the highest at site Ra7 where it is mostly affected by Yangtze River diluted water,and the contribution of terrestrial organic matter was gradually reduced in a short time scale.The circulation system of the East China Sea and anthropogenic activities were the key factors influencing the distribution of organic matter in this area.The lignin vegetation parameters S/V (0.33~1.35) and C/V (0.07~0.26) showed non-woody angiosperm tissues were the main source of lignin in Ra7 and Za6,whilst a mixture of non-woody angiosperm and gymnosperm tissues were indicated for Zb7.The degradation parameters were in the range of 0.30 to 0.60 and 0.39 to 0.63 for Ad/Al and P/(V+S),respectively.These values suggested that a moderate oxidation and a moderate demethylation/demethoxylation had occurred in the cores.