In this study, the Raman scattering of copper phthalocyanine is enhanced by adopting a millimeter-scale oscillating metallic optical waveguide structure. Different from the traditional surface-enhanced Raman spectroscopy (SERS) technology that creates hot spots by designing complex nanostructures of precious metals, we increase the distance between the upper and lower surface metal cladding layers of the metal optical waveguide, which can increase the thickness of the guided wave layer coupling of light energy into guided wave layer, thereby enhancing the interaction between light and matter. Although increasing the thickness of the guiding layer has the risk of a single-mode field strength drop, the advantages are obvious. First, the high mode density facilitated the coupling of incident light energy with the waveguide layer. Second, the excitation light could be incident nearly perpendicular to the waveguide surface, thereby simplifying the optical setup. Finally, the polarization-independent characteristics of the thick waveguide structure contributed to the Raman enhancement.