  Rabi oscillation is a pure quantum phenomenon where the system jumps forth
and back between two quantum levels under stimulation of a microwave, and a
resonance occurs when the energy difference is matched by the photon energy.
Rabi oscillations have been observed in various quantum systems so far, and
especially are used to demonstrate the quantum coherence of quantum bits. In
the present work, we explore Rabi oscillation in a system accommodating the
elusive Majorana bound states (MBSs) under intensive search recently. The
proposed setup is constructed by a quantum dot (QD) and a superconducting
quantum interference device (SQUID), where a semiconductor nanowire with
spin-orbital coupling in the topological state is introduced to form Josephson
junction. When the coupling between QD and the Josephson junction is tuned by
an ac gate voltage, Rabi oscillation takes place among quantum states formed by
QD and MBSs, which makes it possible to reveal bizarre properties of MBSs by
sensing the electron occupation on QD. Especially, one should be able to
observe the fractional Josephson relation $\cos(\pi\Phi/\Phi_0)$ unique to MBSs
with $\Phi$ the magnetic flux applied in the SQUID and $\Phi_0=hc/2e$ the flux
quantum. The system has been investigated in terms of the analytic Floquet
theorem and numerical simulations with fine agreement.
