An energetic plasticizer 6b-nitrohexahydro-2H-1, 3, 5-trioxacyclopenta[cd]-pentalene-2, 4, 6-tryl trinitrate(2) was synthesized from glyoxal and nitromethane via the condensation and nitration reactions with a total yield of 40.90%, and its structure was characterized by elemental analysis, IR, NMR.The single crystal of compound 2 was obtained firstly.It was found that its crystal belongs to the monoclinic system, and its space group is P2₁/n with a=7.792(9)Å, b=8.534(9)Å, c=19.41(2) Å, β=117.624(4)°, M_r=370.16, V=1305(2) ų, Z=4, D_c=1.884 g·cm^-3, λ=0.71073 Å, F(000)=752, μ=0.189 mm^-1, S=1.097, the final R₁=0.0488, and wR₂=0.1289.