Abstract: In this study, seawater and sediment were collected from the near-shore area of Shenzhen and analyzed for radionuclides. The results indicate that, the radioactive concentration of ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs in the seawater are in the range of 12.8-42.6 Bq/m³ (averaged (24.2±8.6) Bq/m³), 3.2-15.6 Bq/m³ (averaged (8.8±3.6) Bq/m³), 529.7-974.1 Bq/m³ (averaged (786.4±158.4) Bq/m³) and 1.7-3.7 Bq/m³ (averaged (2.6±0.7) Bq/m³), respectively. In the sediment, the specific activity are in the range of 17.9-35.0 Bq/kg (averaged (26.5±5.4) Bq/kg), 32.9-59.8 Bq/kg (averaged (43.2±9.1) Bq/kg), 326.2-415.3 Bq/kg (averaged (364.2±32.4) Bq/kg) and 0.9-3.5 Bq/kg (averaged (1.8±0.8) Bq/kg), respectively. The radioactive concentrations of ¹¹⁰Ag^m in the seawater and sediment are all below the detection limit. The radioactive concentration of these radionuclides fall in the range of those obtained from other near-shore areas of China, and no abnormal radioactivity nuclide level are observed in seawater and sediment samples from Daya Bay.