Surface plasmon polaritons (SPPs) propagating on metal surfaces corrugated with periodic grooves are investigated in the mid-far infrared band. Results show that the structured surface can significantly reduce the asymptotic frequency and improve the field confinement of SPPs propagating on it. The influence of the metal absorption loss on the performance of spoof SPPs (SSPPs) is also studied at the same frequency range. It is shown that sub-wavelength field confinement and long-distance propagation can be obtained simultaneously for SSPPs on metal surface corrugated with periodic grooves. The guiding ability of SSPPs supported by the structured surface is further verified by simulating the transmission of electromagnetic waves along it. The proposed surface structure may lead to the design and development of new integrated guided wave devices in mid-far infrared band.