A plasmonic metamaterial is proposed for which an array of subwavelength apertures is pierced into a metallic foil whose one flat surface has been made with periodic rectangle holes of finite depth. Designed surface plasmons sustained by the holes are explored when the size and spacing of the holes are much smaller than those of the apertures. The transmission property of electromagnetic waves through the metamaterials is analyzed. Results show that the designed surface plasmons characterized by the holes could support the transmission resonances of the incident wave passing through the subwavelength apertures, and that the peak transmission wavelengths could be designed by controlling the geometrical and optical parameters of the holes. Example is taken at THz regime. Our work proposes a method to design the peak wavelengths, and may affect further engineering of surface plasmon optics, especially in THz to microwave regimes.