Abstract: In the automatic welding process,the accurate identification and extraction of the welding line has a great influence on the precision and quality of welding process. For the recognition algorithm based on line laser,the deformation of laser will lead to a decline in light intensity due to the line contact with the weld in the threshold algorithm. In this paper,an improved method to extract the center point of V shape weld based on line-laser is presented. Firstly,the Bilateral Filter method was used to smooth the image,which helps to keep the contour of laser line while removing the noise. Then the deformation zone of laser on the V shape weld was extracted by Canny Edge Detection algorithm. The Eroding algorithm was used to change the Structure Light on the weld to a continuous solid closed poly line. The interference line left by the contour of the weld was removed. By the line thinning algorithm,the intersection of laser with the edge contour and center line of the weld was detected. Finally,the position of the center point of the weld was identified by the Line Fitting method.