A new heat flux method is proposed for determining a thermal shock resistance parameter of ceramics. A ring shaped disc specimen is heated by the electro-conductive thin film glazed on its inner surface, and the time to fracture initiation is measured. At the same time, nondimensional thermal stresses occurring in the specimen under various heat flux conditions are theoretically calculated as a function of nondimensional time to give a set of reference curves. By combining the curves with the measured time, voltage and resistivity of electro-conductive film etc., the thermal shock resistance parameter, S/Eα, is easily determined. The experimental date obtained by this method are useful for designing ceramic materials used in firing kilns.