Abstract: The submerged arc welding flux for -101°C low temperature steel developed in this study has good welding process performance, stable arc in welding process, good slag removal performance, excellent weld bead forming and low impurity content in weld metal. The weld deposited metal and its welded joints have excellent low-temperature impact toughness at -101°C. The mechanical properties of the welding material meet the requirements of national standard GB/T 5293, pressure vessel standard NB/T 47018 and related technical agreements.