Objective To assess the impact of Fukushima nuclear power plant accident on the level of radioactive level of the seafood in Nantong. Methods Samples of shellfish, fish, shrimps and crabs were collected quarterly (except fish moratorium), and total alpha and beta ray levels were tested. The pomfret and clams were sent to Jiangsu provincial disease prevention and control center for radionuclide detection in 2017. Results The total alpha and total beta ray levels of clams, golden hooked shrimps, pike crabs, and yellow fish were not correlated between each year (P>0.05), There was no regression relationship between years of total alpha radioactivity level (F(1,5)=0.126, P>0.05), while the total beta ray was the opposite (F(1,7)=4.65, P<0.05).The natural nuclides ²³⁸U, ²³²Th, ²²⁶Ra and ⁴⁰K in clams and pomfret were at background level, and the level of artificial nuclide of ¹³¹I, ¹³⁴Cs and ¹³⁷Cs were less than the detection limit. Conclusion Japan's Fukushima nuclear accident had not affected seawater products in the region for the time being. It was still necessary to continue monitoring the dynamic trends of the radioactivity level of marine products in the sea.