Abstract: The Ni and Cr elements were added in CaF₂-SiO₂-TiO₂-CaO base powder with Ni to Cr mass ratio of 1:1, 2:1, 3:1, respectively, then the self-shield flux cored wires were prepared with 2205 stainless steel strip as wrapping material. Using the prepared welding wires, 2205 duplex stainless steel was arc welded, and the effects of Ni to Cr mass ratio on the microstructure and mechanical properties of the weld seam were studied. The results show that with the increase of Ni to Cr ratio, the austenite phase content in the weld seam increases, the ferrite phase content decreases and the size of austenite phase increases. Without the addition of Ni and Cr elements, the strength of the weld seam was the largest while the plasticity was the lowest, and the impact energy was the smallest, which was 72 J. With the increase of Ni to Cr ratio, the strength of the weld seam decreases while the plasticity and impact energy increase. When the mass ratio of Ni to Cr was 3:1, the impact energy of the weld seam had the highest value of 150 J.