The traditional taxonomic classification is based on the most obvious similarities between species. It has been put in place long before the idea of evolution has emerged. Thus, using the most visible characters, the traditional classification does not accurately estimate the degree of relatedness between species, and it was not its original purpose. DNA barcoding is a modern approach developed to overcome these challenges. DNA barcoding is a system designed to provide accurate, fast and automatable species identification by using short and standardized gene regions as internal species tag. The mitochondrial cytochrome c oxidase subunit I (COI) gene using in worldwide for taxonomic studies. In this paper, we are supposed to explain about DNA barcoding approach for taxonomic studies.