Abstract Crystallization and magnetic properties of Nd 2Fe 14B/α-Fe nanocomposite magnets have been investigated by annealing the as-spun ribbons with magnetic field. The crystallization process was accelerated by field annealing. The hysteresis loop became to be fat by magnetic annealing at 645 °C for 4 min, which was 690 °C for ribbons annealing without magnetic field. The relative content of α-Fe phase was increased from the results of XRD. The strength of the magnetic field had no obvious influence on the remanence and coercivity, but modified the squareness of hysteresis loop.