A large-area high-performance near-infrared absorber based on plasmonic nanostructures is introduced, fabricated and experimentally characterized. The periodic plasmonic nanostructures are prepared by self-assembled template, a charming low-cost technology for making large-area samples. Experimental results show that the absorbance can be as high as 99%. The spectral position of the absorption peak is experimentally demonstrated to be tuned by the geometric dimensions. The physical origin of the absorption effect is theoretically explained as well.