Abstract: The effects of rare earth LaCl3 added to the basic sulfamate solution on electrolyte characteristic and microstructure and properties of electroformed nickel layers were studied .The action mechanism of LaCl3 on the surface of cathodic electrode was discussed.It has been found that the cathodic polarization of the electrodepositing process is increased due to occurring of LaCl3 special adsorption on electrode surface,which could result in crystal refining of electroformed layers.Moreover,the crystal orientation has strong (111) texture,and the micro-hardness could be improved substantially with the addition of LaCl3.