In　order　to　investigate　the　quantitative　relations　of　nitrogenous　compounds　in　the　seal　system　and　dynamic　systems　by　molecule　recognition　technologies,　the　stable　isotope　15N　technology　was　adopted　to　identify　these　nitrogenous　compounds.　Experiment　results　showed　that　it＇s　effective　for　the　δ15N　identification　technology　to　measure　the　quantitative　relation　of　denitrification　reaction.　Furthermore,　the　denitrification　could　enrich　15N　in　its　products,　while　the　nitrification　decreases　the　content　of　15N　in　its　products.