Aiming at the positioning and centerline of typical Vgroove welds in the automatic welding of the crawler welding robot,an automatic welding seam tracking system based on laser vision detection was designed.A twostep positioning method based on the characteristics of laser fringe image was presented.The first step is to establish template matching and use template matching to obtain the laser stripe location.Secondly,the center line of laser stripe was extracted by threshold segmentation algorithm and center value method.Then the Shi-Tomasi algorithm was used to detect the corner points of the center line,and the four inflection points of the weld groove were obtained by fitting the straight line intersection and contrast by scanning column,then the weld center was determined.Through testing the process of real welding tracking,the results show that the average error correction error of the tracking system was within 2 pixels and the average processing time was within 120 ms,which has high accuracy and instantaneity.