ADP-glucose pyrophosphorylase (AGP) plays a key role in regulating starch biosynthesis, which is a heterotetrameric enzyme composed of two large (AGP1) and two small subunits (AGPs). A homology-based PCR was used to clone a cDNA encoding AGP small subunit from Dunaliella parva , which produces starch and lipid. The molecular characterization of the AGPs gene was described. The cDNA of the AGPs (GenBank Accession no. JN033559) was found to contained an open reading frame (ORF) of 1512 bp encoding a 503 amino acid polypeptide. The deduced amino acid sequence of Dunaliella parva AGPs showed significant homology to the known AGPs from Chlamydomonas reinhardtii and Volvox carteri, and contained two conserved domains. The Dunaliella parva AGPs gene cDNA sequence was cloned and its molecular characterization was described by bioinformatics tool. To our knowledge this is the first reported.