Abstract: In order to study the effect of δ-ferrite on the toughness of δ-ferrite in electrodeposited GX8CrNi12 steel,five types of electrodes with different chemical compositions were prepared by using the Balmforth phase diagram to predict the volume fraction of deposited metal in the electrode. Multi-functional X-ray diffraction and metallographic microscope were used to qualitatively and quantitatively determine the metallographic microstructure and volume fraction of the five kinds of electrodeposited metals. The impact toughness of the deposited metal was measured by impact tester. The results show that the impact toughness of GX8CrNi12 steel electrode depends mainly on the content of δ-ferrite.With the increase of δ-ferrite content,the impact toughness decreases.