  In this work, we present a search strategy for heavy charged Higgs boson at
Compact Linear Collider (CLIC) as a future $e^+e^-$ collider. The signal is
charged Higgs boson pair production in two Higgs doublet model (2HDM) followed
by $H^{\pm}\to W^{\pm}H$ and $H\to b\bar{b}$. Here, $H$ denotes the heavy
CP-even neutral Higgs boson of the model. The collider center of mass energy is
chosen to be $\sqrt{s}=1400$ GeV as the second stage of CLIC operation. In this
case, $m_{H^+}<\sqrt{s}/2$ can be explored due to the pair production. It is
shown that the signal of charged Higgs in the mass range 250 GeV $<m_{H^+}<$
650 GeV in fully hadronic final state, containing four $b$-jets from neutral
Higgs and four jets from $W$ bosons, can well be observed on top of the only
remaining standard model background, i.e., $t\bar{t}$. Finally, a measure of
data needed for discovery is expressed in terms of integrated luminosity for
$5\sigma$ at each theoretical hypothesis.
