Abstract: In horizontal position welding, the gravity makes molten metal flow downward and sometimes causes weld defects such as undercut and overlap. To solve this problem the authors propose a new welding process called electromagnetically controlled horizontal welding process and discuss its theory. The result shows that this process is practicable and realizes the aim of controlling weld bead shaping. During the short-circuit transition welding when the welding current is 192 A, there is no defect such as undercut and overlap. Therefore the welding efficiency is increased obviously, and the welding cycle is shortened during the multilayer welding.