The　stereochemical　effect　of　the　chiral　amino　acid　residues　on　the　formation　of　penta-coordinate　phosphorus　intermolecular　mixed　carboxylic-phosphoric　anhydride　(IMCPA)　from　N-phosphorylamino　acids　was　studied　with　density　functional　theory　(DFIP)　calculations　at　B3LYP/6-311G(d,p)　level.　The　reaction　pathways　for　the　formation　of　penta-coordinate　phosphorus　intermediates　with　different　configurations　through　the　carboxyl　oxygen　on　amino　acid　group　attacking　the　phosphoryl　group　from　different　directions　were　simulated　and　the　stereoselectivity　in　the　formation　of　IMCPA　was　discussed.