Trithiocyanuric acid (TTCA) polymer film provides a useful environment for the electrostatic immobilization of functional molecules. Their immobilization characteristics are affected by their polymer structure. TTCA polymer films were prepared by an electropolymerization with aqueous solution at various pH values, and their higher-order structure were evaluated by XPS, zeta-potential and SEM measurements. These results suggested that the acidic solution induced more mercapto groups in the TTCA polymer.