In order to solve the problems of high temperature and high pressure in the synthesis of 1-methyl-3，4， 5-trinitropyrazole （MTNP）， a new method of simple synthesis of MTNP was developed， that is， 4-chlorpyrazole （1） was used as raw material， and MTNP was synthesized by nitration， n-methylation， benzylamine amination and oxidation. The effects of material ratios， temperatures， solvents， debenzylation reagents， and oxidation conditions on the yields of 4-benzylamino-1-methyl-3，5-dinitropyrazole （4）， 4-amino-1-methyl-3，5-dinitropyrazole （5）， and MTNP were investigated. Fourier transform infrared spectroscopy （FT-IR）， nuclear magnetic resonance （NMR） and high performance liquid chromatography （HPLC） were used to characterize the structures of the intermediates and target compounds. The results showed that when the intermediate 4 was synthesized， the molar ratio of n（benzylamine）：n（4-chloro-1-methyl-3，5-dinitropyrazole， 3）=6∶1， the reaction temperature was 35 ℃， and petroleum ether/water was the solvent， the yield was 89.6%. In the synthesis of intermediate 5， concentrated sulfuric acid （98%） was used as debenzyl reagent， and the yield was 95.2%. The yield of MTNP was 60.5% by using intermediate 4 as substrate and “one-pot method” of debenzylation/oxidation. By optimizing the reaction conditions， the total yield of MTNP synthesized from raw material 1 by one-pot method was 41.5% and the purity was 98% （area normalization method）.