The invention provides a copying welding device free of a blind area. The copying welding device free of the blind area comprises a welding gun copying adjusting frame. A welding gun is arranged on the welding gun copying adjusting frame. The welding gun copying adjusting frame enables the welding gun to swing. The invention further provides a copying welding method free of the blind area. The copying welding method free of the blind area comprises the step of welding a curved-weld-joint through the welding gun. One motor is used for driving the welding gun to swing, and copying welding of theweld joint in any shape is conducted through the welding gun by the adoption of an elastic device; the turning tendency of a magnetic base can achieve copying on a weld joint of a workpiece in a gapless manner; welding can be conducted on a non-horizontal weld joint through the magnetic force, generated by a magnet on the magnetic base, acting on the base plate of the workpiece; if obstacles exist on the two sides of the weld joint in the length direction, welding can be stilled conducted at the starting position and ending position of the weld joint, manual follow-up repairing welding is notneeded, the appearance is consistent, and the attractiveness is high; copying welding of different weld joints can be achieved, operation is easy, and the functional cost is low.