In this article, we study the average control of a population dynamic model with age dependence and spatial structure in a bounded domain Ω ⊂ R 3. We assume that we can act on the system via a control in a sub-domain ω of Ω. We prove that we can bring the average of the state of our model at time t = T to a desired state. By means of Euler-Lagrange first order optimality condition, we expressed the optimal control in terms of average of an appropriate adjoint state that we characterize by an optimality system.