The genomic DNA was extracted from porcine Actinobacillus pleuropneumoniae and subjected to PCR using ApxⅠA gene primers. The resulted product was linked to pMD18–T vector and then generated pMD18–T–ApxⅠA recombinant plasmid for bioinformatics analysis. The biochemical results indicated that 1 209 bp target fragment of ApxⅠA was managed to be cloned. And bioinformatics analysis revealed that ApxⅠA protein had a stable physicochemical property and had a phosphorylation site and no glycosylation site. The online signal peptide prediction showed that ApxⅠA protein was hydrophilic protein without trans–membrane domains and signal peptide. Structure prediction revealed its tertiary structure consisted of 25.56% of α–helixes, 23.82% of β–sheets and 50.62% of radon coils.