Abstract: A method for detecting and tracking the non-groove butt joint by using the principle of corner detection based on line structured light vision sensing is studied. It is different from the traditional line structured light sensing method to detect the weld position according to the deformation feature. The proposed method applies for the fact that the laser stripe has obvious gray gradient variation in the weld. The morphological image processing method is adopted to extract the feature of weld center. The gray value of each column in the image is calculated, and the region of interest is extracted by the central difference method. According to the principle of the corner detection method, the sub-pixel coordinates of the weld center can be determined accurately. The actual position deviation of the weld is obtained by using a simple and fast system calibration. Experimental results show that the average error can be kept within 0.1 mm by tracking a butt joint whose width is about 0.2 mm, which can meet the requirement of seam tracking precision.