Nitration of aromatic hydrocarbon and nitrogen heterocyclic by N₂O₅ was summarized. N₂O₅ /nitric acid system is a very powerful nitration reagent and particularly valuable for the nitration of highly deactivated aromatics. N₂O₅ /organic solvent system is a much milder and more selective nitration reagent, which is suitable for the cases that the substrates or products are sensitive to acid or water, and for region-selective O-nitration. Furthermore, the synthesis and pilot-plant-scale process of N₂O₅ were also summarized.