The Vlasov-Poisson-Boltzmann equations can be used to simulate the transportationof charged particles under the electrostatic potential force governed by the self-consistent Poisson equation. In this talk, we talk about the recent results on the spectral analysis for the Vlasov-Poisson-Boltzmann equations and the optimal time decay rates of the global strong solutions. This analysis verify the influence of electric filed on the qualitative behaviors of the VPB system.