The melting point is an important indicator determining the explosives can become the carrier for melt-cast explosives. To obtain the relationship between the molecular structure of explosives and the melting point, the relationship between the molecular structure and the melting point of nitro diazole compounds was investigated. Change relation of the melting point and the parent structure of explosive molecule, the number of substituting group and configuration was concluded and summarized. The regularity between the structure of energetic diazole compounds and the melting point was obtained. Seven types of explosives with low melting point were designed on the basis of pyrazole ring as the basic structural unit, of which the predicted melting point of five explosives is lower than 120 ℃. Results show that the predicted melting point of two kinds of energetic pyrazole compounds: 1-amino-3, 4, 5-trinitropyrazole and 1-methyl-3, 5-dinitropyrazolyl-4-methylnitramine is 112.7 ℃ and 86.5 ℃, respectively. Their detonation performances are better than those of TNT.