Laser　assisted　trimmer　side　cutting　technology　was　studied　to　overcome　the　problems　such　as　micro　cracks,　stress,　burrs　and　edge　waves　existing　in　a　cold　rolling　production　line　of　silicon　steel　side　cutting.　A　finite　element　analysis　model　for　the　laser　hearting　temperature　field　was　established,　the　loading　form　of　a　heating　source　was　determined　and　influences　of　various　processing　parameters　like　laser　powers,　spot　sizes,　and　laser　incident　angles　on　laser　assisted　heating　sheet　materials　were　discussed　according　to　the　actual　process　of　a　cold　rolling　production　line.　These　processing　parameters　were　optimized　in　experiments.　It　is　proved　that　the　temperature　is　about　100°C　when　the　laser　heated　spot　is　moved　to　the　blade　position　of　trimmer.　At　this　time,　the　hardness　of　the　material　drops　to　70%　to　80%　and　the　cutting　forces　is　declined.　As　a　result,　the　wear　of　cutting　trimmer　is　reduced　and　the　life　of　the　cutting　trimmer　is　improved　effectively.