In this thesis we study the unparticle effects on the unitarity constraint of two-body Higgs boson scattering. After a brief review on the Standard Model, we introduce the unparticle stuff and its interaction with Higgs boson from effective field theory. Then we present the general unitarity condition in the quantum theory which can give constraints on the scattering amplitude. By applying unitarity constraint on the process of two Higgs scattering through exchange of the scalar unparticle, the constraints of the unparticle effects are given. It is found that the unitarity upper bound of Higgs boson mass from the Standard Model can be loosen at the region of small unparticle scale dimension du or comparably large unparticle cut-off Λu.