Abstract: A new type of repair electrode for 18Ni maraging steel was developed.Proper chemistry ingredient of core wire and coating was determined.A series of welding experiments and mechanical tests of this electrode were performed.Microstructure and fracture appearance were analyzed by OM,SEM,TEM.The results showed that the electrode had good weldability,small splash and good detachability.After aging treatment,the deposit metal had excellent mechanical properties,low phosphorus,sulphur and diffusible hydrogen content,which was fit in with base metal.