A wideband terahertz metamaterial absorber is proposed based on the phase transition properties of VO₂, which consists of two VO₂ pattern layers, two polyimide dielectric layers and a metal reflector layer. The absorption characteristics, electric field distribution and tunability of the absorber are simulated and analyzed, and the results show that the bandwidth of the designed absorber with an absorption rate of more than 90% is 2.56 THz. The absorber stacks two layers of periodic cells with the same structure but different sizes, effectively extending the bandwidth. Moreover, by controlling the phase transition of VO₂ from the insulating state to the metallic state, the absorptivity can be continuously adjusted. In addition, by studying the absorption performance of the designed metamaterial absorber under different polarization angles and incident angles, it is found that the absorber is polarization independent and absorption insensitive at large incident angles. The designed absorber is expected to be widely used in areas of terahertz communication, imaging and detector.