Efficient　absorption　of　solar　radiation　holds　the　key　to　photothermal　utilization;　however,　realizing　solar　absorber　designs　with　high　absorption　efficiency　remains　challenging.　Herein,　a　nickel-based　metamaterial　selective　solar　absorber　with　a　nanopillar　array　structure　was　proposed　to　realize　nearly　perfect　optical　absorption　over　a　broad　spectrum.　The　average　absorbance　is　up　to　96%　in　the　300-2033　nm　wavelength　range.　Notably,　a　reasonably　detailed　analysis　of　the　physical　mechanism　of　the　proposed　absorber　was　performed　in　this　paper,　attributing　the　exceptional　broadband　absorption　to　the　concurrent　interaction　with　surface　plasmon　resonance,　quarter-wavelength　resonance,　and　electric　dipole　resonance.　The　absorption　efficiency　declines　significantly　when　lambda　＞　2.5　mu　m,　with　only　20%　absorptivity　at　lambda　=　6　mu　m　in　the　radiation-absorbing　transition　region.　This　decline　is　desirable,　as　it　contributes　to　reducing　the　emissivity　in　the　mid-infrared　range　and,　therefore,　prevents　self-radiation.　The　results　demonstrate　that　the　selective　absorber　possesses　the　potential　to　capture　solar　energy　within　a　broadband,　while　avoiding　undesirable　self-radiation,　thereby　enhancing　the　integral　efficiency　of　the　solar　energy　conversion　system.　Moreover,　the　absorption　spectrum　shows　insensitivity　to　polarization　and　angle　of　incidence.　The　selective　solar　absorber　proposed　here　offers　excellent　performance　with　a　simple　structure,　showing　great　promise　in　the　field　of　photothermal　conversion.