Abstract：In order to facilitate marine sources metallothionein, safe and high-level expression system as an efficient tool in Bacillus subtilis was reconstructed in this study. The metallothionein (MT) gene was obtained by PCR amplification using Ostrea plicatula genome DNA as a template and sub-cloned into the expression plasmid pHT43 via pMD19-Tvector. Then the plasmid was electro-transformed into B. subtilis WB800N. The molecular weight of expressed fusion protein SUMO-Op-MT was about 23 kD, which was confirmed by Western blotting. This showed that the soluble fusion protein SUMO-Op-MT was expressed in the host bacteria. At the same time, the fermentation broth of recombinant Bacillus subtilis was detected by HPLC, and the results also showed that the soluble protein Op-MT was expressed in recombinant Bacillus subtilis successfully. Furthermore, through the detection of MT activity in recombinant bacteria, it was found that recombinant bacteria’s tolerance to heavy metal cadmium was increased, indicating that active MT was successfully expressed in recombinant bacteria. It provides a theoretical basis for the future development of heavy metal antidote of natural and efficient marine sources.