A renormalization procedure for the perturbative manipulation of Vlasov-Poisson equation has been proposed in this paper. By the graphical expansion method the theory is shown to be renormalizable to any order, and the renormalized propagator is given. The physical meaning of the coherent terms and the absolute incoherent terms is analyzed. The correct expression for the renormalized dielectric function is given and its significances are discussed. By comparison with previous renormalization theory, it is pointed out that this procedure is a true complete renormalization.