  The quasiparticle interference of the spectroscopic imaging scanning
tunneling microscopy has been investigated for the surface states of the large
gap topological insulator Bi$_2$Te$_3$ through the T-matrix formalism. Both the
scalar potential scattering and the spin-orbit scattering on the warped
hexagonal isoenergy contour are considered. While backscatterings are forbidden
by time-reversal symmetry, other scatterings are allowed and exhibit strong
dependence on the spin configurations of the eigenfunctions at k points over
the isoenergy contour. The characteristic scattering wavevectors found in our
analysis agree well with recent experiment results.
