<p>In recent years, terahertz metamaterial absorbers have attracted considerable attention due to their strong potential in applications such as communication and sensing, enabled by their ability to efficiently absorb electromagnetic waves through precise structural design. Nevertheless, many existing absorbers feature fixed and relatively narrow bandwidths and single-functional designs, which may limit their adaptability in broadband or tunable applications. To overcome these limitations, this work proposes a switchable multimodal metamaterial absorber based on synergistic regulations of two phase-change materials. The proposed absorber adopts a multilayer composite architecture consisting of, from top to bottom, a patterned vanadium dioxide (VO₂) layer, a polyimide dielectric layer, a VO₂ film, a patterned gallium arsenide (GaAs)–Au layer, a TOPAS dielectric layer, and a gold ground plane. By exploiting the complementary tunability of VO₂ and GaAs, the absorber enables flexible switching among single-band, dual-band, and broadband absorption modes within a unified structural framework. Moreover, the proposed absorber exhibits excellent shielding effectiveness across different operational states, highlighting its strong potential for improving system compatibility and environmental adaptability in multi-band communication, sensing, and other terahertz applications under complex electromagnetic conditions.</p>