Abstract: The electron beam welding with filler wire has been developed recent years in order to change the weld compositions to avoid the hot cracks, to strengen the joint, or to fabricate a complex metal object by overlaying.Weld section shape is considered as an important character in this processe.Thus, it is necessary to study the relationship between the welding parameters and weld cross section shape.Through careful control of the focusing current, and measuring the characters of weld section (section area, penetration, reinforcement, weld width, and weld width in the middle of penetration, etc.), the effect of focusing current on weld section shape was investigated.This is useful for optimizing the process.