Abstract：The Qinzhou Bay is the biggest bay in Guangxi, with rich harbor resources. It is one of the most important areas for developing marine economy. In recent years, as the human impact has become more and more serious, the problems of geological environment have also become more and more complicated and have made increasing pressure to local environment. Guangzhou Marine Geological Survey (GMGS) of China Geological Survey (CGS) is conducting a project of marine geological environmental survey along Guangxi coast in Beibu Gulf between 2006 and 2010. Some soil samples were sent to Germany to test Hg. According to the soil sample test, this paper analyzes the characteristics of Hg distribution in the bay. The results show that Hg is mainly derived from ships and rivers. The values of Hg are higher outside the gate of the Qinzhou Bay than inside the gate, and become lower towards the offshore. Test of core JX05 shows that the Hg values are getting higher from bottom to top. Below 70cm of the core, the values of Hg become stable. It can be inferred that human impact along Qinzhou coast began 700 years ago and has became more and more serious since 130 years ago. In general, the values of Hg are lower than the standard value taken from the Baltic Sea of Germany, which means that the environment of the Qinzhou Bay remains good at present. Nevertheless, more attention should be paid to the protection of the environment and to the de-pollution work, as the environment has already been influenced by the development.