Surface sediments were collected by high-resolution sampling from the Changjiang River Estuary and its adjacent shelf in March, 2014. Grain size composition, Specific Surface Area (SSA), Total Organic Carbon (TOC) and stable carbon isotope composition (δ¹³C), n-alkanes and its related indices in sediments were analyzed to discuss the high-resolution distribution patterns of sedimentary organic carbon (OC) and n-alkanes in this region. A three end-members mixing model based on Principal Component Analysis (PCA) and Monte-Carlo Simulation was constructed to characterize the sources of sedimentary OC quantitatively. The results showed that TOC contents were 0.45%±0.16%, which were relatively higher in coastal mud area than offshore sandy area. Absolute contents (Σn−Alk) and relative contents (Σn−Alk/TOC) of total n-alkanes (C₁₄ to C₃₅) were (1.42±0.73) μg/g and (0.34±0.21) mg/g , respectively. There was a strong odd to even carbon preference of long-chain n-alkanes in muddy sediments, while there was an even to odd carbon preference of short-chain n-alkanes in sandy area. Inputs from the Changjiang River, the Old Yellow River Estuary and small rivers in the Zhe-Min coasts and hydrodynamic sorting restricted the transport and dispersal patterns of n-alkanes. The results of the three end-members mixing model indicated a mixture input of marine, soil and higher plant derived OC in this region. Among them, sedimentary OC was dominated by marine source (42.70%±18.18%), increasing from coast to outer sea gradually. Contributions of soil OC and higher plant OC were 28.99%±15.37% and 28.31%±17.12%, respectively. Influenced by hydrodynamic forces, obvious differentiation of these two terrestrial OC pools occurred during transport after entering into ocean. Soil OC was mainly associated with fine grains, and was transported southward along the Zhe-Min coast, while higher plant derived OC was mainly transported along northeast direction in the Changjiang River Estuary.