2　mm-thick　6061-T6　aluminum　alloy　and　SPCC　cold-rolled　steel　plate　are　used　to　obtain　aluminum　steel　composite　joints　with　both　fusion　and　brazing　characteristics　by　means　of　wire　filling　laser　brazing　method.　The　influences　of　pre-coated　flux,　groove　bevel　angle,　bevel　morphology　and　solder　composition　on　the　microstructure　and　mechanical　properties　of　brazing　joint　are　studied.　The　results　show　that　pre-coating　flux　can　greatly　improve　wettability　of　filler　metal.　The　mechanical　properties　of　laser　brazing　joint　are　better　when　60°　groove　is　prefabricated　on　the　side　of　steel　base　metal　than　when　45°　groove　is　prefabricated..　When　the　prefabricate　groove　angle　of　steel　material　is　60°,　and　the　laser　power,　welding　speed,　wire　feeding　speed,　laser　defocusing　amount,　offset　center　of　the　laser　spot　center　are　3.1　kW,　0.5　m/min,　2　m/min,　-8　mm,　+0.6　mm,　respectively,　with　ER2319　Al-Cu　filler　metal,　the　average　and　maximum　tensile　strength　of　the　joint　are　respectively　147　MPa　and　159　MPa,　the　interface　layer　presents　short　whisker　shape,　the　interface　layer　is　5-8　μm　in　thickness,　the　Cu　element　is　dissolved　in　Al-Fe　brittle　phase　by　replacing　Fe　elements　to　reduce　its　brittleness.　With　ER5356　Al-Mg　filler　metal,　the　average　tensile　strength　of　the　joint　is　118　MPa　when　the　laser　power　is　3　kW,　the　interface　layer　presents　coarse　saw　tooth　shape,　and　consists　of　FeAl2,　Fe2Al5　and　FeAl3　phase,　the　interface　layer　is　8-12　μm　in　thickness,　the　Mg　element　is　gathered　at　the　outside　of　brittle　phase,　and　it　has　no　obvious　inhibitory　effect　on　the　growth　of　Al-Fe　brittle　phase;　with　ER4043　Al-Si　filler　metal,　the　average　tensile　strength　of　the　joint　is　129　MPa　when　the　laser　power　is　3　kW,　the　interface　layer　presents　small　saw　tooth　shape,　the　interface　layer　is　3-4.5　μm　in　thickness,　the　Si　element　is　dissolved　in　Al-Fe　brittle　phase　to　inhibit　its　growth.　©　2020　Journal　of　Mechanical　Engineering.