Mechanical alloying (MA) is a widely used processing technique to prepare metastable or nanophase materials in a cost effective fashion. In this study, mechanically alloying FeCo based nanomagnetic alloys was included. Scanning electron microscope (SEM), X-ray diffractometer (XRD), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) were used to characterize the as milled powders. The effect of additional elements P and B on the powder size, microstructures and magnetic properties is discussed. It showed that the addition of P and B could reduce the powder size more effectively. The addition of elements P and B during MA of FeCo magnetic alloy also led to the formation of spherical nanocrystallines instead of banded microstructures in MA FeCo without these additions.