Abstract: TOPTIG is a new welding technology of tungsten inert gas (TIG) with feeding wire robotic welding process. It is different from conventional TIG with filling wire in the characteristics of droplet transfer. The welding platform of TOPTIG is built to collect the high-speed photography and electric signals at the same time in the welding process under different conditions using high-speed camera and an electrical signal collecting system to study the characteristics of droplet transfer. It is found that when the droplet is in contact with the molten pool, which will cause the deflection of arc. The droplet transfer can only be realized by means of the contact with molten pool, where the gravity of droplet and the surface tension between the droplet and the molten pool are the major force to promote the transfer. A reasonable matching range exists between the peak current and the wire feeding speed, which will be narrowed with the increase of the peak current.