The Ni-Fe alloy coatings were prepared by electro-deposited method, and the effects of the saccharin content in the electrolytes on the microstructure of the coatings were studied by using X-ray diffractometry(XRD), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The results show that the saccharin content in the bath affects the plating rates and the current efficiency remarkably. As the saccharin content increases, the grain size of the Ni-Fe alloys decreases. The average grain size of the deposits varies from 13 nm to 10.8 nm as the saccharin content increases from 0 g/L to 8 g/L. Accordingly, the microhardness of the as-cold deformed samples increases from Hv 600 to Hv 656.