<p>The surface properties and thermodynamic properties of high-temperature coal tar pitch (HCTP) were determined by inverse gas chromatography at 323.15–353.15 K, and its surface dispersion free energy, Lewis acid–base constant, Florry-Huggins interaction parameters and Hildebrand solubility parameters of HCTP were determined. In the range of 323.15–353.15 K, the surface dispersion free energy of HCTP increased with the increase of temperature. Furthermore, the acid constant <i>K</i>_a of HCTP calculated as 0.259, the base constant <i>K</i>_b is 3.1, demonstrated that HCTP is an amphoteric alkaline material. The Florry-Huggins interaction parameters showed that tetrahydrofuran and butanol were good solvents for HCTP. The Hildebrand solubility parameters of HCTP at 323.15–353.15 K were 17.33, 16.76, 15.98, and 14.68 (J/cm³)^0.5, respectively, and showed a downward trend with the increase of temperature.</p> Graphical abstract <p></p>