Abstract: During dual-beam laser welding of 3D T-beam, the welding structure is complicated and special, the 3D welding path is difficult to fit, and the welding deformation is large. The real-time measurement of 3D T-seam welding was achieved, to solve the mentioned problems, with two laser visual sensors on a Six-axis NC welding machine tool. The actual 3D double-beam welding path was generated using 3D welding path control technology with 3D model of T-seam. Dynamic compensation in dual-beam welding process o f 3D T-seam was achieved using dual-seam real-time closed-loop tracking technology. The actual welding results show that the established dual-beam welding seam tracking technology meets the requirements of dual-beam laser welding.