In recent years, increasing bio-pollutants entering into natural ecosystems has become one of the major challenges of human everyday life. The heavy metals caused by industrial activities mainly is considered the most dangerous polluters due to biological and chemical characteristics of inseparability. In organism's cells in order to reduce the toxic effects of metals embedded mechanisms that can include proteins with high affinity property to metal chelater. Metallothioneins (MTs) are a group of low molecular weight proteins and rich in amino acid cysteine that have the ability to have binds with various metals because of thiol groups. Plant metallothioneins, according to the classification done based on the distribution pattern of the amino acid cysteine were categorized in 4 type. Until further research in relation to metallothioneins expression analysis in different tissues by RT-PCR using isoform-specific has focused and levels has examined less of a especial role in protein. This study has been done in order to investigate the role of OsMTI-3a protein which is one isoform of type 3 of rice in tolerance ratio to heavy metals and metal-binding ability of these isoforms was performed. in order to with designing of specific primers, sequence of the gene encoding of this protein in shear position Eco R1 and Hin d??? in downstream T7 promoter was cloned and Then to expressional strain Rosetta (DE3) was transformed. Production of control strain Rosetta-pET41a large scale and recombinant strain Rosetta-pET-41a-OsMTI-3a has done by induction of expression by IPTG. Recombinant strain of bacteria tolerant to metals was investigate by Growth curves drawing in presence of cadmium chloride salts, magnesium sulfate, zinc sulfate and nickel chloride. Furthermore removal amount of metal by bacteria producing OsMTI-3a protein has done with measuring metal concentrations in the culture medium by atomic absorption spectroscopy (AAS) .Using affinity chromatography, purification of recombinant proteins and GST control, GST-OsMTI-3a was done and By comparing them in conditions in vivo and in vitro by reaction with DTNB substance as well as changes in absorbance, the preoccupation and capacity bind to metal GST-OsMTI-3a recombinant protein was measured. The results of the evaluation of recombinant strains tolerance to metals showed that GST-OsMTI-3a recombinant protein cause increasing in tolerance of bacterial cells to metals of nickel, cadmium and zinc became while the production of this protein did not cause increasing in the cell tolerance of bacterial ¬ Rosetta-pET-41a-OsMTI-3a to the copper metal. from the DTNB reaction with recombinant proteins produced in the in vivo and in vitro conditions was determined that preoccupation of the GST-OsMTI-3a protein in evaluated metals are Cd Ni Zn Cu respectively. Measurement and comparison the metal amount in the phase of culture medium of control and recombinant strains with AAS showed that GST-OsMTI-3a recombinant protein has caused a reduction in the metals cadmium, nickel and zinc with amounts 17.2, 12.6 and 8.4% of The culture medium respectively while expression of this gene didn’t show noticeable decreasing in removal of copper metal in culture medium. Finally, according to the achieved results it seems that OsMTI-3a protein has the ability to bind to cadmium, nickel and zinc metals.