The dielectric properties of Ag/ZnO composite material are investigated and a strong low-frequency dispersion phenomenon is found. The experimental results are systematically studied in the frequency range of 0.1—107 Hz and in the temperature range of 173—473 K. By means of normalization of conductivity, it is found that samples with different Ag contents show similar mechanism of dielectric loss, which is suggested as electron jumping between deep levels. In addition, it is also found that the dependence of E1mA on Ag content is similar to that of αlf on Ag content, which is a novel result in the research of varistor materials. The results can be fully understood by means of universal power law.