This work investigates the manipulation of terahertz surface plasmons (SPs) on a semiconductor surface by applying an external static magnetic field. The dispersion relations of the coupled surface magnetoplasmon under the Voigt configuration in the semiconductor-insulator-semiconductor structure are derived. For a TM-polarized wave that is normally incident onto a semiconductor film with periodic narrow grooves on both surfaces, the applied external static magnetic field with the Voigt configuration redshifts the frequencies of the SP-induced resonant tunneling. This phenomenon is attributable to the reduction in the effective plasma frequency by the applied magnetic field.