A nano-structure that supported the localized surface plasmon (LSP) was fabricated by using thermal evaporation and annealing processes to enhance the nonlinear absorption of chalcogenide Ge₂₈Sb₁₂Se₆₀ (GSS). The Z-scan experiment was carried out to measure the nonlinear refractive and nonlinear absorption of the fabricated samples. By analyzing the characteristics of the transmission spectra of the samples, the mechanism of the nonlinear absorption enhancement was revealed. Finally, the influence of the GSS thickness on the enhancement nonlinear absorption was studied. The proposed LSP nano-structure is easy in fabrication due to the lithography-free process, which provides significant reference for designing nonlinearty enhancement devices.