Based on the data of marine environmental investigation obtained from the Qinhuangdao sea area in July 2015, the contents of heavy metals in seawater, sediments and some sea creatures were analyzed by flame atomic absorption method. The results show that the contents of Cr in seawater at Qinhuangdao sea area were better than the values of the first degree of Water Quality Standard, but the seawater is polluted by Pb, Cu, Ni and Zn in different degrees. Pollution of Cu is so serious that exceeds the four degree of Water Quality Standard. The average contents of Pb in surface sediments are slightly higher than the first degree of Standard for Marine Sediments Quality, showing slight pollution. Cu, Ni, Zn and Cr are all significantly lower than the first class Marine Sediment Quality Standard, showing no pollution. The contents of Zn and Cuin shellfish had comparatively higher concentrations than the otherswhile Ni has the lowest concentration, this phenomenon may be attributed to the different accumulation ability of heavy metals in shellfish.