  The harmonic metric for a moving Kerr black hole is presented in the second
post-Minkowskian approximation. It is further demonstrated that the obtained
metric is consistent with the Li\'{e}nard-Wiechert gravitational potential for
a moving and spinning source with an arbitrary constant velocity. Based on the
metric, we also give the post-Newtonian equations of motion for photon and
massive test particle in the time-dependent gravitational field.
