  We study a generic Higgs boson and a top quark associated production via
model-independent flavor-changing neutral-current couplings at the LHC,
including complete QCD next-to-leading order (NLO) corrections to the
production and decay of the top quark and the Higgs boson. We find that QCD NLO
corrections can increase the total production cross sections by about 48.9% and
57.9% for the $Htu$ and $Htc$ coupling induced processes at the LHC,
respectively. After kinematic cuts are imposed on the decay products of the top
quark and the Higgs boson, the QCD NLO corrections are reduced to 11% for the
$Htu$ coupling induced process and almost vanish for the $Htc$ coupling induced
process. Moreover, QCD NLO corrections reduce the dependence of the total cross
sections on the renormalization and factorization scales. We also discuss
signals of the $tH$ associated production with the decay mode $t \rightarrow
bl^{+}E \slash_{T}, H \rightarrow b\bar{b}$ and $t\bar{t}$ production with the
decay mode $\bar{t} \rightarrow H\bar{q}, t\rightarrow bl^{+}E \slash_{T}$. Our
results show that, in some parameter regions, the LHC may observe the above
signals at the $5\sigma$ level. Otherwise, the upper limits on the FCNC $Htq$
couplings can be set.
