  We study the heavy charged Higgs boson (from 800 GeV to 1500 GeV in this
study) in production associated with a top quark at the LHC with the collision
energy $\sqrt{s}=14$ TeV. Such a heavy charged Higgs boson can dominantly decay
into a top quark and a bottom quark due to its large Yukawa couplings, like in
MSSM. To suppress background events and to confirm the signal, we reconstruct
the mass bumps of the heavy charged Higgs boson and the associated top quark.
For this purpose, we propose a hybrid-R reconstruction method which utilizes
the top tagging technique, a jet substructure technique developed for highly
boosted massive particles. By using the full hadronic mode of $p p \to H^{\pm}
t \to t tb$ as a test field, we find that this method can greatly reduce the
combinatorics in the full reconstruction and can successfully reduce background
events down to a controlled level. The sensitivity of LHC to the heavy charged
Higgs boson with two $b$ taggings is studied and a $9.5\sigma$ significance can
be achieved when $m_{H^\pm} =1 \textrm{TeV}$.
