The microstructure with which a hard magnetic phase precipitates from the soft magne ticmatrix, is observed in nanocomposite Pr2Fe14B-αFe. The magnetic hysteresis loo ps are simulated by micromagnetic finite element method. The dependence of reman ence, coercivity and maximum energy product on the width of soft phase are discu ssed in detail. Although a single hard magnetic phase behavior is observed, the coercivity decreases monotonically with the increase of soft phase width from 0 to 12 nm. The obtained maximum energy products are 184 and 674 kJ/m3 for isotropic and anisotropic magnets, respectively.