The　effects　of　groove　angle,　focal　length　of　lens　and　defocusing　amount　on　the　melting　behavior　of　the　materials　in　the　grooves　are　studied　by　utilizing　the　fiber　laser　to　scan　and　weld　aluminum　alloy　V-grooves.　The　results　show　that　the　V-groove　can　focus　fiber　laser　apparently,　and　the　better　melting　effect　in　grooves　can　be　obtained　when　the　focal　length　is　300　mm,　the　defocusing　amount　is　0~10　mm,　and　the　incident　angle　is　5°.　Further　analysis　demonstrates　that,　this　is　attributed　to　the　low　absorptivity　of　aluminum　to　fiber　laser　at　the　Brewster　angle.　In　addition,　because　of　the　energy　losing　for　each　laser　reflection,　the　overmuch　number　of　reflection　of　fiber　laser　in　V-grooves　is　inappropriate.　©　2017,　Chinese　Lasers　Press.　All　right　reserved.