4, 6-Dinitro-7-hydroxybenzofuroxan sodium salt(NaDNP)was synthesized via nitration, substitution and annulation using 3-bromoanisole, etc. as materials in yield of 45.6%. Its purity, morphology and structure were confirmed by high performance liquid chromatography, Na elemental analysis, video microscope, ¹H NMR, ¹³C NMR, FT-IR spectra. Its thermal behavior was studied by DSC and 5 s delay time deflagration point. Its sensitivity properties was studied by impact, flame, hot wire and electrostatic spark sensitivity. Results show that the thermal decomposition peak temperature of NaDNP at a heating rate of 20 ℃·min^-1 is 283.11 ℃ and 5 s delay time deflagration point is 300.3 ℃, revealing that NaDNP has good heat resistance. Its impact sensitivity H₅₀ is 37.4 cm, flame sensitivity H₅₀ 18.5 cm, hot wire sensitivity E₅₀ 1.278 mJ, electrostatic spark sensitivity E₅₀ 4.3 mJ, which is more insensitive than lead 2, 4, 6-trinitroresorcinate (LTNR). NaDNP can be used as an intermediate of primary explosive.