A planar plasmonic sensor based on textured metallic disk is demonstrated, where a simple and integrated method is used to excite the spoof localized surface plasmons (LSPs). Multipolar plasmonic resonant modes can be easily observed on the textured metallic disk. The multipolar resonant modes of the textured metallic disk are calculated by eigenmode solver of CST microwave studio. The resonant frequencies agree very well to the results observed from the extinction cross section (ECS). The numerical simulations verified that the spoof LSP resonances are highly sensitive to the change of surrounding environment.