The invention discloses a multi-degree-of-freedom automatic welding device. The multi-degree-of-freedom automatic welding device comprises a base plate. The base plate is fixedly connected with a stand column through a thrust bearing, and the stand column is fixedly connected with a translation support. A large belt pulley is arranged in the middle of the stand column and is in transmission connection with a small belt pulley through a driving belt, and the small belt pulley is fixedly connected with a first motor. A controller is arranged on the base plate, and the first motor, a second motor, a third motor and a fourth motor are electrically connected with the controller through wires. The multi-degree-of-freedom automatic welding device is simple in structure, easy and convenient to operate, low in cost and complete in function. A horizontal sliding block is driven by the fourth motor to move, finally a lifting support and a welding bar are driven to horizontally move, and movementis rapid and reliable. A lower sliding block and an upper sliding block are driven by the third motor to move, finally the welding bar is driven to vertically move, and motions are accurate and effective. Angle adjustment of a welding rod in the horizontal plane and the vertical plane is achieved through the first motor and the second motor correspondingly. The welding range is broad, and weldingis flexible and accurate.