Sodium pentazole salt was prepared by treating 2, 6-dimethyl-4-(2H-pentazol-2-yl) phenolate with m-chloroperbenzoic acid (m-CPBA) and ferrous bisglycinate [Fe(Gly)₂] under low-temperature conditions, thereinto, m-CPBA and Fe(Gly)₂ were oxidizer and catalyst, respectively. The synthetic conditions were optimized, as following:the molar ratio between arylpentazole, Fe(Gly)₂ and m-CPBA was 1:3:4.5, the reaction time was 24 h and the reaction temperature was-45 ℃(crude yield of 28%). The effect of different oxidizing cleavage reagents on the yield of sodium pentazole salt was studied and the reason for the low yield of sodium pentazole salt was analyzed. In addition, sodium pentazole salt and the reaction by-product (2, 6-dimethylcyclohexa-2, 5-diene-1, 4-dione) were characterized by X-ray single crystal diffractometer (XRD), NMR (¹⁵NMR and ¹H NMR), FT-IR, mass spectrometry and elemental analysis. Based on these results, the mechanism of oxidizing cleavage of the C─N bond in arylpentazole by m-CPBA and Fe(Gly)₂ was speculated.