A novel infection-age structured eco-epidemiological model with saturation incidence is constructed. The model is regarded as an abstract non-densely defined Cauchy problem, and the condition of the existence of the interior equilibrium is derived. By employing the method of integrated semigroup and the Hopf bifurcation theory for semilinear equations with non-dense domain, we obtain that the model undergoes a Hopf bifurcation around the interior equilibrium which manifests that this model has a non-trivial periodic orbit that bifurcates from the interior equilibrium when bifurcation parameter τ crosses the bifurcation critical value τ0. In other words, the sustained periodic oscillation phenomenon appears. To support and extend our theoretically analytic results, numerical simulations are performed.