Abstract: Radionuclides in the surface sediments from Lufeng nuclear power plant and its adjacent sea area of the South China Sea were measured using γ spectroscopy method. It was shown that the uranium decay series were in disequilibrium in the surface sediments, where ²¹⁰Pb relative of ²²⁶Ra were excess and ²²⁶Ra relative of ²³⁸U were deficient. Meanwhile, the thorium decay series were close to decay equilibrium. Compared with the radioactive content of sediments in some sea areas of China, the specific activity of ²³⁸U and ²²⁸Th were at medium level. The content of ⁴⁰K, ²²⁶Ra, ²¹⁰Pb, ²²⁸Ra and ¹³⁷Cs were close to sediment of the northeastern South China Sea. In a whole, the radioactivity level of sediments from Lufeng nuclear power plant and its adjacent sea area had no significant difference with historical data and was in the normal background range.