A high oxygen balance compound-tetranitroacetimidic acid(TNAA), was synthesized via concentrated nitric acid nitrification and organic solvent extraction using 1, 1′-diamino-2, 2′-dinitroethene(FOX-7) as raw material. The yield and purity of TNAA obtained by four kinds organic solvents (dichlormethane, trichoromethane, tetrachloromethane and ethyl acetate) were compared. The thermal behavior of TNAA was studied by DSC and TG. Results show that dichloromethane is determined as the best extraction solvent and its yield and purity are 95.0% and 99.4%, respectively. At a heating rate of 10 K·min^-1, the initial temperature, peak temperature and melting enthalpy of melting endothermic peak of TNAA are 84.8 ℃, 87.8 ℃ and 61.7 J·g^-1 respectively, the initial temperature, peak temperature and decomposition heat of exothermic decomposition peak are 117.7 ℃, 131.4 ℃ and 934.8 J·g^-1, respectively. The apparent activation energy (E) and pre-exponential constant (A) of thermal decomposition reaction obtained by Kissinger method are 124.7 kJ·mol^-1 and 10^16.1 s^-1, respectively. The self-accelerating decomposition temperature (T_SADT), critical temperature of thermal explosion (T_b), and thermodynamic parameters ΔH^≠, ΔS^≠ and ΔG^≠ of thermal decomposition reaction of TNAA at T=T_p are 102.3 ℃, 112.2 ℃, 121.5 kJ·mol^-1, 61.2 J·K^-1·mol^-1 and 98.0 kJ·mol^-1, respectively.