Abstract: Some radionuclides in surface marine sediments from Yangjiang nuclear power plant and its adjacent sea area were measured using HPGe γ spectrometer. The specific activities of ²³⁸U, ²²⁶Ra, ²¹⁰Pb, ²²⁸Th, ²²⁸Ra, ⁴⁰K and ¹³⁷Cs were 75.2~102.0, 32.6~38.6, 86.9~148, 54.3~71.3, 40.9~70.6, 580~660 and < 0.16~3.82 Bq/kg_DW, with the mean of 82.4±5.2, 35.5±2.0, 121.7±14, 60.2±3.1, 57.1±3.1, 621±29 and 2.21±0.31 Bq/kg_DW, respectively. The specific activities of ¹³⁴Cs, ^110mAg, ⁵⁸Co and ⁶⁰Co were below the limit of method. Ratio(²²⁶Ra/²³⁸U) and Ratio(²¹⁰Pb/²²⁶Ra) were 0.35~0.48 and 2.63~4.17, with the mean of 0.43 and 3.43, respectively. It was shown that the uranium decay series was in disequilibrium in the surface sediments, where ²¹⁰Pb relative of ²²⁶Ra were excess while ²²⁶Ra relative of ²³⁸U was deficient. The average value of Ratio(²²⁸Th/²²⁸Ra) was 1.06, ranging from 0.96 to 1.36. It was shown that ²²⁸Th and ²²⁸Ra was in equilibrium in the surface sediments. No obvious correlationship was found among the specific activities of radionuclides in sediments, the grain size characteristics and the offshore distance.