Abstract: A robotic welding device employing a flexible guide rail comprises: a control box (2) pre-storing various welding processes and generating a welding parameter; a wire feed mechanism (7) feeding a welding wire to a welding gun (4); a flexible guide rail (8) attached to a welding component with the flexibility thereof; a welding robot comprising a robot body (3) and a welding gun (4), the robot body (3) being movably disposed on the flexible guide rail (8) along the same, and the welding gun (4) being disposed on the robot body (3) and controlled by the same to weld the welding component; a demonstrator (6) signally connected with the welding robot and the control box (2), controlling, a traveling path and an operation position of the welding robot, and adjusting oscillation and welding operations of the welding gun (4) according to an instruction of the control box (2); a remote control terminal (11) signally connected with the control box (2) so as to remotely monitor and configure the welding parameter, and