Abstract: The information contained in the Dielectric response of materials can be used to investigate the micro-structure and charge motion of dielectric materials. The Debye model describes the polarization of non-interact dipoles floating in viscous medium, which seldom occurs in solid dielectrics. Empirical modified models based on the Debye model, such as the Cole-Cole model, Davidson-Cole model, Havriliak-Negami model, provide a physical interpretation of the morphology properties and charge motion of a dielectric, furthermore, the parameters in these empirical model have no direct physical significance. The Dissado-Hill model proposed by Dissado L A and Hill R M is a theoretical model which takes the interaction/correlation effect between the relaxing entities into account. The parameters in the Dissado-Hill model have definite physical meaning. The present paper discusses the Dissado-Hill model as well as the concept of "cluster" in depth. The Dissado-Hill model has two sub-models: one describes the dielectric response for permanent dipole relaxation, termed the Dissado-Hill loss peak model; the other one is for relaxation due to mobile charge separation over restricted ranges, termed the Dissado-Hill QDC model. The difference between QDC process and dc conductivity has been distinguished both physically and mathematically. By combining the Dissado-Hill model and the equivalent circuit method, the dielectric response of high temperature vulcanization silicone rubber has been analyzed in-depth, in which a quasi-dc process can be clearly observed.