This paper use the method of plane tracking and inclined plane interpolation to weld the container′s corrugated plate,the acquirement of broken line intercept point is the key point. A laser sensor is designed,which can detect broken line intercept point of the corrugated plate. The sensor placed in front of welding torch adopts initiative laser to illuminate the surface of the corrugated plate,the reflection light pass through the limit hole then illuminate linear Charge Coupled Device (CCD),the sensor obtains the distance from spot to CCD by calculating the exposure width. Using least squares to regress plane and inclined plane into two lines and get the intersection by calculating equations of two lines and then to get the accurately broken line intercept point. Surface condition has little influence on photograph sample signal forms by the way model template in order to get boundary between exposure and no exposure. The sensor has high line precision and meets the requirement of seam tracking by experiment. The tolerance of broken line intercept point is in ±0.5 mm ,it provides great helpful evidence to get broken line intercept point when container corrugated plate is welded automatically.