This paper describes the development of a reconfigurable 3D profile measurement system for welding robot. The system consists of a PC based vision camera and a stripe-type laser diode. The total system is assembled into a compact module which can be attached to the endeffector of welding robots. Especially, the developed system is designed to operate at different working distances. For this purpose, the reconfigurable mechanism which adjusts the focal length and the relative position between the camera and the laser diode is devised. These two configurations are automatically changing, according to the current working distance. Most parts of image processing such as camera calibration, correction of distortion, and line extraction are implemented and running on the PC. After measuring the welding profile, the 3D shape of the parent metal is obtained and some useful features for robot manipulation are calculated.