The utility model relates to a three-dimensional adjustable fixing device of an automatic welding torch. The device is characterized by comprising an upward and downward moving device (1), a left and right moving device (2), a front and back moving device (3), and a rotary connecting rod device (4), wherein each moving device consists of a C-shaped frame, a slide block, a slide block guide rod and a transmission screw rod, and the rotary connecting rod device (4) consists of an upper connecting rod (41), an upper clamp (42), a connecting rod (43), and a lower clamp (44). The device has the advantage that the welding torch fixedly arranged at the lower end of the connecting rod (43) is adjusted and driven by a hand wheel to move up and down, left and right, and back and forth, the angle position of a nozzle of the welding torch is rotated and adjusted through the connecting rod (43), and the adjusting movement is stable, so the three-dimensional adjustable fixing of the welding torch is realized, the welding position is more accurate, and the welding quality is improved.