  We study the effects of two-body Higgs boson scattering by exchanging
unpsrticles. The unparticle contribution can change the standard model
prediction for two-body Higgs boson scattering partial wave amplitude
significantly leading to modification of the unitarity constraint on the
standard model Higgs boson mass. For unparticle dimension $d_\U$ between 1 and
2, the unitarity constraint on Higgs boson mass can be larger than that in the
SM. Information on unparticle interaction can also be obtained.
