In　order　to　investigate　the　quantitative　relations　of　nitrogenous　compounds　in　the　seal　system　and　dynamic　systems　by　molecule　recognition　technologies,　the　stable　isotope　N-15　technology　was　adopted　to　identify　these　nitrogenous　compounds.　Experiment　results　showed　that　it＇s　effective　for　the　delta　N-15　identification　technology　to　measure　the　quantitative　relation　of　denitrification　reaction.　Furthermore,　the　denitrification　could　enrich　N-15　in　its　products,　while　the　nitrification　decreases　the　content　of　N-15　in　its　products.