Abstract: The distribution of n-alkanes in surface sediments were studied in Yangtze Estuary, the concentrations of n-alkanes ranged from 17.3×10^-9 to 2132.3×10^-9, and the average concentration was 821.2×10^-9.The minimum concentration of n-alkanes was detected near Yangtze Estuary, except for station S5 and S6, the n-alkanes concentration decreased gradually following the transport of Yangtze River diluted water.The range of CPI_13-22 ranged from 0.43 to 0.72, and CPI_23-32 varied from 1.13~2.81 in sediments, TAR_HC did not exceed 1except for station S5 and S7, while the ratio of LMW/HMW ranged from 2.07 to 54.85, the n-alkanes biomarkers revealed that the short-chain n-alkanes (C < 25) had significant even carbon preference, and were mainly derived from marine sources.