3, 5, 7-Trinitro-1-azaadamantane was synthesized from 1, 3-dinitrobenzene via nitration, reduction, Henry reaction and condensation, the overall yield was 21.5%. The structures of intermediates and target compound were characterized by IR, NMR and melting point apparatus. The effects of molar ratio of HNO₃ to H₂SO₄, mixed acid dosages and charging ways on the nitration reaction were investigated. Intermediate product 1, 3, 5-trihydroxymethyl-1, 3, 5-trinitrocylohexane was synthesized by "stepwise" and "one-pot" process and the reaction time of Henry reaction was shortened by increasing the reaction temperature. The effects of acids and bases on condensation of 1, 3, 5-trihydroxymethyl-1, 3, 5-trinitrocylohexane with ammonia were studied, the reaction conditions and workup procedures were modified. The thermal stability of 3, 5, 7-trinitro-1-azaadamantane was studied by thermogravimetry (TG) and differential scanning calorimetry (DSC). Results show that the optimum process conditions of nitration are determined as: n(HNO₃): n(H₂SO₄)=1: 1.5, m(mixed acid): m(1, 3, -dinitrobenzene)=23 and the charging way is adding 2/3 mixed acid first followed by the other 1/3 after 24 h, with the yield of 70.7%. The time of Henry reaction is shorten by 12 h by increasing the reaction temperature, and the yields of "stepwise" and "one-pot" are 61.8% and 83.5%, respectively. The reaction time of improved condensation is shortened to 3 days, and the simplified workup procedures are filtration, decoloration and recrystallization successively, and both acids and bases reduce the yield of condensation. The decomposition of 3, 5, 7-trinitro-1-azaadamantane starts from about 225 ℃ and the exothermic peak temperature is 331 ℃, which demonstrates that the target compound possesses good thermal stability.