The high absorptivity of metamaterial absorbers originates from the local surface plasmon resonance (LSPR) in the interface between metal nanoparticles and dielectric medium as well as the resonant absorption induced by the micro-cavity composed of a metal nanoparticle layer, a dielectric medium layer and a metal reflector layer. The absorbance of a metamaterial absorber is closely related to the size and shape of nanoparticles and the material and thickness of dielectric medium. A metamaterial absorber which has nearly perfect absorption at the wavelength of 1.2 μm in the near infrared waveband is designed and optimized. Taking this design as a blueprint, a series of devices with different dielectric medium thicknesses are prepared by using the nanoimprint lithography (NIL). The absorption properties of these devices are studied quantitatively by using the reflection absorption spectroscopy. The experimental results show that the metamaterial devices prepared by NIL have the advantages of good process reliability and high machining precision. The absorption change trend measured in experiment is consistent with the theoretical expectation and the absorption is high.