Exogenic indole-3-acetic acid (IAA) hormone has been known to be produced by plant-associated bacteria for regulating plant growth and development. The genus of Bacillus as the most common colonizer of the plant has the capability to produce this hormone. IAA n-acetyltransferase is an enzyme that plays role in the production of tryptophan-dependent IAA hormone on bacteria. Generally, enzymes as proteins have certain characteristics according to their function. The aim of this study was to compare and analyze the protein structure characteristics of IAA n-acetyltransferase enzyme produced by two species of Bacillus, such as B. subtilis and B. amyloliquefaciens. The analytical modeling based on NCBI database showed that protein structure characteristics produced by these species are similar to 3D protein models and the types of amino acids that build up the enzyme. However, the amount of α-helix, β-sheet and the number of amino acids that make up it remains different. In addition, another similarity was also found that the enzymes of the two species do not have transmembrane proteins. These results can contribute to theoretical knowledge related to the characteristics of structural proteins from enzymes involved in IAA hormone production.