This paper investigates the hydroionic transport processes at the near surface of cement-based porous materials under external drying-wetting (D-W) actions. A basic multiphase model is retained and reviewed critically for moisture transport under D-W actions. The multiphase model fails to account for the substantial difference between moisture diffusivities during drying and wetting. The multiphase model is adapted for moisture transport under D-W actions through the respective mechanisms of moisture transport during drying and wetting. Together with the associated ionic transport, a global hydroionic model is established and the corresponding numerical scheme is developed to solve the near surface transport problem. Then, systematic experiments are performed on two concretes with high and low porosities for transport properties and hydroionic transport under D-W actions with pure water and salt solution. Experimental data validate the global model, while some fundamental aspects of hydroionic modeling are discussed.