Nd 40 Fe 30 Co 15 Al 10 B 5 bulk amorphous prepared by high energy milling shows a coercivity of 650kA∕m with a Curie temperature of 645K. The controlled nanocrystallization enhances the coercivity to 1600kA∕m and the remanence ratio is equal to 0.59. The coexistence of two crystalline magnetic phases, ferromagnetic Nd2(Fe,Co,Al)14B, and antiferromagnetic Nd6(Fe,Co,Al)14 are revealed by x-ray diffraction, high-resolution transmission electron microscopy, magnetization measurements, and Mössbauer spectrometry. The grain size for optimal magnetic properties is around 30nm. The nucleation process may play a leading role in the high magnetic behavior.