  The Newman-Penrose formalism is used to deal with the quasinormal
modes(QNM's) of Rarita-Schwinger perturbations outside a Reissner-Nordstr\"{o}m
black hole. We obtain four kinds of possible expressions of effective
potentials, which are proved to be of the same spectra of quasinormal mode
frequencies. The quasinormal mode frequencies evaluated by the WKB potential
approximation show that, similar to those for Dirac perturbations, the real
parts of the frequencies increase with the charge $Q$ and decrease with the
mode number $n$, while the dampings almost keep unchanged as the charge
increases.
