In this work, the surface properties of polyethersulfone (PES) were analyzed by inverse gas chromatography (IGC). Five n-alkanes (n-C-6, n-C-7, n-C-8, n-C-9, and n-C-10) were chosen as apolar probes to characterize the surface dispersive free energy at different temperatures. Acetone (Acet), dichloromethane (DCM) and tetrahydrofuran (THF) were chosen as polar probes to detect the Lewis acid-base parameters, i.e. the Lewis acidic number K-a and Lewis basic number K-b. It was found that the surface dispersive free energy was 32.09, 30.41, 28.52, and 27.21 mJ/m(2) at 60, 70, 80, and 90 degrees C, respectively. The Lewis acidic number K-a is 0.086 and Lewis basic number K-b is 1.523. Compared with other polymers characterized by IGC, the PES belongs to a strong basic polymer material.