It is demonstrated that a periodic metallic wavy-structure can be easily fabricated on elastomeric polydymethylsiloxane (PDMS) substrates. The period of the wavy-structure is controllable by varing the thickness of the deposited silver film. The elastomeric-gratings can excite surface plasmon on Ag/air interfaces, the resonant wavelength can be tuned to a range of 3.5% by applying an external mechanical strain. Our experiments demonstrate the possibility of a new type optical filter with tunable wavelengths. In addition, a new nanoprojection lithography (NPL) is proposed to manufacture plasmonic nanogratings. The period of the wavy-structure on PDMS substrates could be decreased to nanometer scale after decreasing its thickness of the different upper light-penetrable ultra-thin film layer. Hence, a low-cost, self-assembly, elastomeric PDMS wavy-structures are used as the interference modules, with their periods and amplitudes largely controlled by the applied mechanical strain in the synthesis process. Well-defined plasmonic grating couplers with desired feature sizes and wavelengths of operation were obtained. Moreover, this NPL may enable large-area and flash manufacturing of plasmonic nanogratings with tunable array periods. Finally, manufacturing large-area periodic metal/dielectric rectangular hole arrays on glass substrate are achieved using this NPL technology. The transmission for normal incident light through a silver film perforated with rectangular hole arrays with different aspect ratio are measured. It shows that resonance peak shifts to long wavelength and becomes broader by increasing the value of the aspect ratios.