To avoid the influence of Cl- in 1,3,5-triamino-2,4,6-trinitrobeneze(TATB), the synthetic technology improvement of TATB without Cl- was studied starting from phoroglucinol (PG), which were three steps including nitration, alkylation and amination. The affecting factors such as reactant reagent, mole ratio of material, temperature and concentration of reaction were studied. The yield of each step reaction reaches up to 91%. The structures of TATB and its intermediates were identified by ¹H NMR,¹³C NMR, and mass spectra. There are two special aspects in the improved technology: one is the new nitration agents NH₄NO₃/H₂SO₄, and other is usage of ethanol as the reaction solvent. The optimized nitration conditions are :molar ratio of PG to NH₄NO₃ 13.3, reaction concentration 0.356 mol·L-1, temperature below 10 ℃. 