Pyruvate phosphate dikinase (PPDK) catalyzes the reversible conversion of AMP, phosphoenolpyruvate (PEP) and pyrophosphate (PPi) to ATP, pyruvate and inorganic phosphate (Pi). It is a key enzyme in gluconeogensis and photosynthesis that is responsible for reversing the reaction performed by pyruvate kinase in Embden-Meyerhof-Parnas glycolysis. A cDNA clone for the Dunaliella parva PPDK was isolated by sequencing. Then the 3'-RACE and 5'-cDNA amplification were conducted based on the obtained sequence. The molecular characterization of the PPDK gene was described.The Dunaliella parva PPDK gene cDNA sequence was 3249 bp, which contained 2595 bp coding region and 654 bp 3'-untranslated regions. The deduced amino acid sequence of Dunaliella parva PPDK showed significant homology to the known PPDK from Volvox carteri and Chlamydomonas reinhardtii. This study provided foundation for further research on the function analysis and overexpression of PPDK genes. To our knowledge this is the first reported.