Nd-Fe-B nanoparticles was prepared by coprecipitation method in aqueous solution. The parameters for the composition are the concentration of borohydride solution and the pH of the solution containing metal ion. The B and Nd contents were found to vary with pH and borohydride concentration. The crystal structure of the synthesized nanoparticles was identified with X-ray powder diffraction (XRD). The size and shape of nanoparticles were confirmed by transmission electron microscope (TEM). The magnetization curves of nanoparticles and nanocomposite were characterized with vibrating sample magnetometer (VSM). Energy dispersive X-ray spectrometer (EDS) was used to characterize composition of Nd-Fe-B nanoparticles.