Abstract: The influence of th ree kinds of RE elements and RE metal mixture on the oxygen, nitrogen content and proe sensitivity in the weld of self-shielded flux-cored wire was investigated in the present study. Significant findings of this study revealed that the oxygen content and pore sensitivity in the weld were reduced with the increase of RE element addition, among which the RE metal mixture most effectively depressed the formationof porosity. The effect of RE element addition on the nitrogen content in the weld was insignificant due to the oxidization from the early deoxidization stage. However, the RE elements could effectively fix the nitrogen so that the nitrogen content in the weld could be controlled to certain beneficial ranges. It was also found out that proper RE element addition could increase the toughness of the weld metal and improve its microstructure by grain refinement.