Plasmons induced by topological insulator (TI) Bi 2 Se 3 micro-ribbon arrays have been experimentally observed recently ( Nature nanotechnology 2013, 8, 556-560 ). In this letter, the surface plasmons excited by TI Bi 2 Se 3 micro-disk arrays are investigated by the methods of full-wave numerical simulations. Numerical simulation results show that thin Bi 2 Se 3 micro-disk arrays can support dipolar plasmon resonances in the terahertz (THz) regimes and the absorptions can be tuned by the structure parameters. In addition to the plasmon mode, two phonon-mode responses are also observed, which confirms the experimental results of micro-ribbon arrays. Our work further proves that TI can be a good candidate of plasmonic platform.