The outer membrane protein, omp A, of Aeromonas veronii has a role in the virulence of the organism and is a potential candidate for vaccine development. In this study, omp AⅠ of Aeromonas veronii strain WA106 was cloned and sequenced, then, it was expressed in Escherichia coli BL21. The nucleotide sequence of omp AⅠ gene was 1 023 base pairs(Gen Bank Accession NO.KC748024), which showed 100% homology with that of A. veronii(NO.AB290200.1). This predicted protein was composed of 340 amino acid residues. Its molecular weight was 35.78 ku and isoelectric point was 5.18. The protein was a hydrophilic protein containing alpha helix and random coil with percentage of 35.0% and 49.7%, respectively. The tertiary structure, quaternary structure prediction showed that omp AⅠ protein contained two peptide chains. SDS-PAGE showed that the actual value of the fusion protein was consistent with the expected result. It will facilitate further study of the role of omp AⅠ protein. The outer membrane protein, omp A, of Aeromonas veronii has a role in the virulence of the organism and is a potential candidate for vaccine development. In this study, omp A I of Aeromonas veronii strain WA106 was cloned and sequenced, then, it was expressed in Escherichia coli BL21. The nucleotide sequence of omp A gene was 1 023 base pairs (Gen Bank Accession No. KC748024), which showed 100% homology with that of A. veronii (NO.AB290200.1). This predicted protein was composed of 340 amino acid residues. Its molecular weight was 35.78 ku and isoelectric point was 5.18. The protein was a hydrophilic protein containing alpha helix and random coil with percentage of 35.0% and 49.7%, respectively. The tertiary structure, quaternary structure prediction showing that that omp A I protein contained two peptide chains. SDS-PAGE showed that the actual value of the fusion protein was consistent with the expected result. It will facilitate further study of the role of omp A protein.