In this work, the issue of magentic hardening of soft phase in nanocomposite permanent magnetic materials has been investigated using one-and three-dimensional models. For the same microstructure, it is found that the coercivity is decreased and the low-field demagnetization curve keeps unchanged when the anisotropy constant of magnetic hard phase is decreased in anisotropic one-or three-dimensional samples. Therefore, the drop in anisotropy of magnetic hard phase will not lead to the increase of remanence and maximum energy product (BH)max. According to the simulation results of isotropic three-dimension samples, both the remanence and (BH)max will be obviously decreased by the drop in anisotropy. As a result, enhancing the anisotropy and/or enlarging the grain size of magnetic hard phase is one of the means to improve the hard magnetic properties of nanocomposite permanent magnetic materials.