Abstract: Based on the viscoelastic theories and the theories of fractional derivatives,the fractional Zener model and its constitutive equations are established.After that,its parameters of mechanical properties are derived based on the above model,such as the creep function,relaxation function,complex modulus and its loss ratio of viscoelastic bodies obeying fractional Zener model.Finally,its behavior of creep and relaxation,including its variation of partial parameter with frequency,is analyzed through a numerical example.The results show that:The creep and relaxation of viscoelastic materials can be well described by the fractional Zener model.The materials storage modulus will approach to one and the loss ratio change quickly when the frequency is small,approaching to a rubbery state,closing to the elastomer.However,when the frequency is high,the rate of dissipation tends to be stable quickly and when the frequency increases,the loss ratio begins to drop until reaching its maximum value.