Abstract: Organic carbon, carbon stable isotope (δ¹³C) and lignin were applied to explore the distribution and degradation of terrigenous organic matters in the sediment of intertidal mudflat of Yellow River estuary. The results showed that, the organic carbon content varied between 0.06% and 0.40%, and δ¹³C ranged from-24.4‰ to-20.4‰, which implied multiple sources of organic carbon in study area.Σ8 varied between 0.13 and 0.54 mg/10g dw with an average of 0.23 mg/10g dw, decreasing from the mouth of Yellow River to northern and southern mudflats.Λ8 varied between 0.49 and 2.42 mg/100 mg OC, with an average of 1.35 mg/100 mg OC, decreasing from southern to northern mudflats. LPVI showed that, lignins were primarily derived from herbaceous and woody tissues of angiosperms and the contribution of herbaceous and woody tissues altered seasonally in study area. Lignin degraded through oxidation and demethylation/demethoxylation, in which demethylation/demethoxylation contributed more.