The mechanism of magnetization reversal processes in the nanocomposite Sm2Fe17N3/alpha -Fe magnets has been investigated on the basis of the rotational hysteresis energy W-r calculated from the magnetic torque curves T. From the studies it results that the magnetization reversal in these magnets is governed by the incoherent mechanism. Moreover, field dependence of the coercivity H-J(c) of minor hysteresis loop indicates that coercivity in the nanocomposite Sm2Fe17N3/alpha -Fe magnets is controlled by nucleation mechanism.