Abstract: To overcome the drawbacks of triditional structured-light sensor for field-teaching welding robot,off-line programming technique for virtual sensor is introduced.Firstly,the system architecture is designed,then the simulated sensor auto-modeling function is developped,the featured stripe profile for welding object is extracted based on the imaging principle of sensor in virtual scene,and at last actual featured profile recognition by using the programming result is discussed.Experiments on complex weld seam tracking and initial welding point search for strcutured component are executed,and results show the system can enhance the applicability and automation of structured-light sensors in robotic welding.