We propose an approach to evaluating the thermal-shock resistance of solid bodies in a thermal-shock schedule based on the development of elastic waves of compression (expansion) and the final value of the velocity of the thermal waves. A model is put forward and also a calculation equation for the destructive drop in temperature ΔTp in the thermal-shock schedule. The magnitude characterizing the dissipation of energy during thermal loading equals the ratio of the velocities of the thermal and longitudinal sonic waves in the solid body. During thermal loading of the solid body over the entire external surface it is necessary to take into account the superpositioning of the waves, and the possibility of the sudden increase in the stress on the wave front to a value exceeding the tensile strength of the material, with significantly lower temperature gradients. The calculation equation obtained for determining the destructive temperature limit agrees qualitatively with the known experimental data, and enables us to predict the thermalshock resistance of the traditional refractories, and to determine means of creating new material resistant to thermal shock.