3,5-Dinitropyrazole ammonium salt was synthesized with 3-nitropyrazole asprimary substance by nitration and rearrangement. Their structures were confirmed by IR, NMR, MS and elemental analysis. Reaction condition was optimized by HPLC and TLC. The optimization reaction temperature was 147 ℃, reaction time was 77 h and the conversion was 96.5%. Dinitropyrazole ammonium salt was directly gained by ammonia gas neutralization.