  We study the compatibility of the unitarity bound and the 8TeV LHC on the
effective theory of the scalar dark matter. In several signals of effective
interactions, mono-jet with missing energy events are studied. We found that,
at least, if the dark matter mass is about 800GeV or heavier, contributions of
events violating the unitarity are not negligible. The unitarity conditions in
the 14TeV LHC are also calculated.
