Abstract: The welding of cast iron with nickel-iron electrodes is in general susceptible to hot-cracking.In this paper,the hot-cracking test machine (type HRL-1) based on the theory of critical deformation speed was used.The effects of rare earth,C,Si,Mn,Co,Cu,S and P elements on hot-cracking were investigated.The optimum RE,C,Co and Si con-tents of the weld metal were determined.Content higher or lower than the respective optimum value would result in the reduction of hot-cracking resistance.Mn,Cu,S and P increase the hot-cracking susceptibility of the weld metal.The reasons of these phenomena were discussed.The comprehensive utilization of the RE,C and Co elements can remarkably improve the hot-cracking susceptibility.