The growth morphology and structure of deposits during the initial stages of amorphous Ni-P electrodeposition was studied using atomic force microscopy (AFM), X-ray diffraction (XRD) and transmission electron microscope (TEM). Combined electrochemical and surface analytical measurements showed that the electrocrystallization process follows a three-dimensional instantaneous nucleation and growth mechanism. The structure of the Ni-P deposits progressively changed from polycrystalline to amorphous state with increasing electroplating time. Additional electrodeposition was carried out on amorphous carbon film at potential -650mV (SCE) for 5s in the same bath for plating Ni-P alloy. It was confirmed that the formation of crystal Ni at initial stage of electroplating Ni-P amorphous alloy was not caused by the epitaxial relationship between the crystal Ni and the crystal substrate and there was a nucleation process in the electrodeposition of amorphous alloy.