<p>A multifunctional terahertz metamaterial device assisted by vanadium dioxide (VO₂) is proposed. Leveraging the property that VO₂ can switch from an insulation state to metal state, the device can achieve linear-to-circular (LTC), linear-to-linear (LTL) polarization conversion, and wideband absorption. The investigation findings indicate that when VO₂ is in the insulating state, the structure can accomplish the corresponding LTL and LTC polarization conversions in the band of 1.0 -3.1 THz and 3.1–6.1 THz, respectively. When VO₂ is in the metallic phase, the device can achieve over 90% absorption from 3.10 THz to 4.95 THz, with the relative bandwidth of 46%. Furthermore, the impacts of structural dimensions, terahertz wave incident angles and polarization angles on the operating characteristics of multifunctional metamaterial structures have also been explored. The reported multifunctional metamaterial device demonstrates promising application in the area of terahertz technology research and intelligent application.</p>