Jiaozhou Bay is a semi-closed bay located in Shandong Province, China. Using investigation data on Hg in bottom waters in April and July 1989, this paper analyzed the contents and distributions, and identified the rapid sedimentation processes of Hg. Results showed that Hg contents in bottom waters April and July were 0.064-0.109 μg L−1 and 0.012-0.017 μg L−1, respectively. These contents were up to Grade I and II for Hg in Sea Water Quality Standard (GB 3097-1997). The pollution level of Hg in bottom waters in Jiaozhou Bay in 1989 was slight. By means of vertical water’s effect, there was a rapid sedimentation process in the bay mouth in April 1989, while in July 1989 a rapid sedimentation process was in the bay center. In general, HG contents in bottom waters would be relatively high/low in case Hg contents in surface waters were high/low. By means of vertical water’s effect, the sedimentation processes of Hg were rapid, and a big part of Hg could be migrated to sea bottom.