For interpreting the production mechanism of surface-wave plasmas sustained aiong a metal rod,electromagnetic simulation on the electromagnetic field distributions and particle-in-ce11/Monte Carlo collision (PIC/MCC) simulation of the ionization process are present.The results show that the enhanced electric field of surface plasmon polaritons (SPPs) can be excited in the ion sheath layer between the negative-voltage metal rod and the surface-wave plasmas,which is responsible for maintaining the plasma discharge.Moreover,the spatio-temporal evolutions of plasma density and electric fields are simulated by the PIC/MCC model.It is further suggested that the expanded ion sheath layer can extend the length of plasma domain by increasing the plasma absorbed energy from SPPs.