The thermodynamics of adduct crystallization of terephthalic acid (TA) in amide solvents, such as N,N-dimethylacetamide (DMAC) and N-methyl-2-pyrrolidone (NMP), was studied in this paper. The results showed that the molecule ratio of TA and solvent in the TA-DMAC and TA-NMP adduct crystals is about 1:2. With poor thermal stability, the dissociation temperatures of the TA-DMAC and TA-NMP adduct crystals are about (341 and 313) K, respectively. The adduct crystallization is an exothermic process; the crystallization enthalpy of the [TA.2DMAC] adduct is about -34.00 kJ.mol(-1), and that of the [TA.2NMP] adduct is about -31.12 kJ.mol(-1). Finally, analysis of the liquid-solid equilibrium indicated that the concentration difference between the solubility of adduct crystals and the notional TA solid may result in the automatic adduct crystallization process.