Based on four-wave mixing (FWM) coupled-mode equations for guided op tical pulses in magneto-optical nonlinear fiber,the numerical computation of the FWM power tra nsfer function (PTF) under various magnetic fields is done for the parallel and orthogonal states of polarization (SOP) of the input light.Also we experimentally measure the influence of the magneto-optica l effect on the FWM power transfer function (PTF) for the corresponding two initial situations of ma ximal and minimal idler power.The experimental data is basically in agreement with the theoretical resu lts.Our researches show that under appropriate applied magnetic field,the extinction ratio performan ce of the fiber-based regenerators can be improved,and the magnetic field dependency of the output id ler power is the most sensitive for the case with orthogonal SOP.