Seam　tracking　is　a　basic　condition　to　ensure　a　fine　welding　shape.　In　order　to　meet　this　requirement,　the　researchers　have　put　forward　a　variety　of　sensors　and　some　of　them　have　been　applied　to　practice　successfully,　such　as　contact　sensor,　arc　sensor　and　vision　sensor.　Laser　vision　sensor　has　been　proven　to　be　one　of　the　most　successfully　technology　for　its　many　advantages.　In　this　paper,　based　on　laser　visual　sensing　technology,　a　seam　tracking　system　is　established　with　an　embedded　microcontroller　LPC1768.　With　this　system,　a　real-time　tracking　algorithm　is　proposed　and　the　seam　tracing　process　is　realized　under　a　smaller　error.　Finally,　the　tracking　errors　resources　and　their　influence　have　been　simulated　and　analyzed.