The nuclear-grade Ni-base ENiCrFe-7 welding electrodes were developed by the optical designing of coating formula and composition of core wire. The microstructure of ENiCrFe-7 filler metals was observed by optical microscopy. The fracture morphology was observed and fracture mechanism was analyzed by scanning electron microscopy（SEM）. The precipitates of grain and grain boundaries were determined by energy dispersive spectrometer（EDS） on the SEM. The mechanical properties and intergranular corrosion resistance were tested. The results showed that the microstructure of ENiCrFe-7 filler metals was columnar austenite;the very small precipitates were observed at the grain and grain boundary. The strength,elongation,bending property and intergranular corrosion resistance of filler metals were qualified,and the impact properties performs well,which was more than 80% of the technical requirements. The fracture morphology was ductile fracture. The metal compounds contained Cr,Fe,metallic oxides contained Ti,Al and second-phase particle contained Nb were found along the migrated grain boundaries by EDS.