  The potential of the non-Standard Model heavy Higgs bosons in 2HDM at a muon
collider is studied. The pair production of the non-SM Higgs bosons via the
universal gauge interactions is the dominant mechanism once above the kinematic
threshold. On the other hand, single Higgs boson production associated with a
pair of heavy fermions is also important in the parameter region with enhanced
Yukawa couplings. Both $\mu^+\mu^-$ annihilation channels and Vector Boson
Fusion processes are considered, as well as radiative return $s$-channel
production. Different types of 2HDMs can also be distinguishable for moderate
and large values of $\tan\beta$.
