Abstract: The influence of wire extension on welding current and arc voltage and the influence of welding current on arc characteristc of twin-wire indirect arc gas shielded welding were investigated. With the increasing of wire extension, welding current is decreased. With the increasing of welding current, the melting rate of cathodal wire raises obviously, and the anodal melting rate increases slowly. They are both decreased with arc voltage increasing; the droplet refines with arc current increasing. The twin-wire indirect arc gas shielded welding has various arc forms.