  We investigate the implication of unparticle exchange for the possible
Sommerfeld enhancement in dark matter annihilation process. Assuming the
unparticle exchange during WIMP collision, we solve the Schr\rm\ddot{o}dinger
equation for the effective potential, and find that the Sommerfeld enhancement
factor is dictated by the scale dimension of unparticle as 1/v^{3-2d_{\UP}}.
Numerically the Sommerfeld enhancement could be {\cal O}(10-10^{3}).
