Abstract: To solve the problem that the low temperature high manganese steel lacks matching electrode, a basic welding electrode for the all-position welding of LNG tank from low temperature high manganese steel is developed, and optimized by combining the welding test results and engineering application demands. The microstructures and mechanical properties of deposited metal and welded joint by the optimized electrode are tested and analyzed. Results show that weldability of the optimized electrode is good, and that the electrode is suitable for the all-position welding. The yield strength, tensile strength and impact energy at 196 ℃ of the deposited metal by the electrode reaches 568 MPa, 722 MPaand 71 J, respectively. The microstructure of the weld is austenite structure, strengthened by solution and dispersed carbide.