Abstract: Before the operation of Changjiang nuclear power plant (CNPP), gross beta radioactivity in seawater, marine sediments and marine organisms was investigated in the coastal area near CNPP. Our observations were compared with those investigated in other terrestrial and marine environment. The results suggested that: (1) Gross beta in seawater ranged from 0.040 to 0.074 Bq/L with the mean value of 0.054 Bq/L, which were slightly lower than those near Daya bay nuclear power plant, and the offshore Bohai sea, the Yellow sea, and the South China sea. (2) Gross beta in marine surface sediment ranged from 257 to 925 Bq/kg, with the mean value of 653 Bq/kg, which was at the same level as those in the coastal areas of Hongkong, Qingdao and Yangjiang. (3) Gross beta in marine organisms ranged from 8.7 to 63.8 Bq/kg. The mean value of gross beta in sea fishes (56.7 Bq/kg), shrimps (63.4 Bq/kg) were significantly higher than that in shellfishes (24.0 Bq/kg). The results were expected to provide important baseline values and help to assess the radioecological risk from the nuclear power plant operation on the coast.