5-Aminotetrazolium nitrate(5-ATN) was synthesized from 5-aminotetrazole monohydrate(5-AT·H₂O) and concentrated nitric acid. The effects of nitric acid dosage, reaction time and reaction temperature on the yield of 5-ATN were discussed. The proper synthesis conditions determined by orthogonal experiments were as follows: 5 g 5-AT, 15 mL nitric acid, reaction temperature 20 ℃ and reaction time 15 min, with the yield of 92.6%. Compared with previous studies, the reaction temperature and reaction time decrease while the yield is improved. SEM picture shows that the surface of 5-ATN is smooth, and hellogh humidity storage tests show that the water absorption of product is reduced.