nhaA（Na⁺/H⁺ antiporter A） was cloned from Escherichia coli Top10 by PCR,with primers designed according to public nhaA sequences.The open reading frame of nhaA gene has 1167 bp in length and encodes a protein of 388 amino acid residues.The estimated molecular weight and isoelectric point of the putative protein were 41.3 kDa and 9.23,respectively.Components of amino acids encoded nhaA contained 25 basic amino acids,19 acidic amino acids,211 hydrophobic amino acids and 63 polar amino acids.The predicted secondary structure of the protein had about 50% alpha helixes,18% extend-ed strand,7% beta turn and 25% random coil.Hydrophobic analysis indicted that nhaA was a hydropho-bic protein.nhaA contained 11 transmembrane segments.It shared 100 %,98 %,95 % and 92 % ho-mologies in DNA sequence level with E.coli DH5α,E.coli HS,E.coli SECEC SMS-3-5 and E.coli CFT073,respectively.Molecular cloning and bioinformatics analysis of nhaA in Escherichia coli Top10 will be helpful for the further analysis of nhaA.