3,4-dinitropyrazole(DNP) was synthesized from pyrazole via N-nitration, rearrangement and C-nitration. N-nitration was improved for a safe synthesis of N-nitropyrazole and carried out by addition of pyrazole/acetic acid solution into nitric acid/acetic anhydride mixture. In addition, C-nitration conditions were optimized as follows:molar ratio of 3-nitropyrazole/nitric acid 1/2, nitration temperature 55-60 ℃, time 1 h. DNP′s total yield could be up to 55%, and purity 99%. The structures of the intermediate and the product were confirmed by IR, NMR, MS and element analysis.