A tunable broadband bandpass filter is proposed, which is based on vanadium dioxide (VO₂) metamaterial. The simulation results show that the 3 dB bandwidth of this filter is 1.71 THz with the central frequency of 5.19 THz and the largest transmission rate of 0.77. Furthermore, this filter can maintain stable broadband transmission performances within the incidence angles of 0°~40°. The physical mechanism of this kind of filter performance is investigated based on the equivalent circuit of this filter and its surface current distributions at the resonance frequencies. Owing to the unique phase transition property of VO₂, the bandwidth of the filter can accordingly change from 1.71 THz to 2.31 THz by tuning the conductivity of VO₂. The proposed metamaterial filter possesses the advantages of structural simplicity, broadband performance, and tunable property, which makes it possible to find promising applications in THz communications, sensing and other emerging areas.