The invention fuses a 3D vision reconstruction technology, an off-line programming technology and a weld joint tracking technology to realize unmanned welding sites, and provides an off-line programming laser weld joint tracking system based on 3D vision. The specific operation process is that a 3D camera is installed above a welding workpiece, remote triggering photographing is conducted after the workpiece is installed, and point cloud data of welding sites such as a workpiece and a clamp are obtained; and according to the off-line programming laser weld joint tracking system, three technologies of 3D visual model reconstruction, offline programming and laser welding joint tracking are fused and applied, so that unmanned welding site is realized. At present, the laser welding joint tracking technology can solve the problem of frequent demonstration due to large change of a part of welding paths, robot machining can be directly generated through off-line programming, however, based ona standard model, the increasingly mature 3D vision reconstruction technology is applied to welding application, and through the welding site reconstruction, the cumbersome demonstration of a weldingprocedure on the welding sites is reduced, and the welding efficiency is improved.