  We investigate Andreev reflection (AR) resonant tunneling through a
precessing spin which is coupled to a normal metallic lead and a
superconducting lead. The formula of the AR conductance at zero temperature is
obtained as a function of chemical potential and azimuthal angle of the spin
precessing by using the nonequilibrium Green function method. It is found that
as the local spin precesses in a weak external magnetic field at Larmor
frequency $\omega_l$, the AR tunneling conductance exhibits an oscillation at
the frequency $2\omega_l$ alone. The amplitude of AR conductance oscillation
enhances with spin-flip tunneling coupling increasing. The study also shows
that spin-orbit interaction in tunneling barriers is crucial for the
oscillations of AR conductance. The effect of spin-flip tunneling coupling
caused by spin-orbit interaction and local spin precessing on resonant behavior
of the AR conductance are examined.
