Copper　and　its　alloys　are　widely　applied　in　electronic　industry,　automotive　industry,　and　refrigeration　and　air-conditioning　industry.　Traditionally,　brazing　and　soldering　were　used　to　join　them.　However,　those　methods　have　some　shortages　such　as　low　efficiency　and　pollution.　In　this　paper,　a　CW　Nd:YAG　laser　with　a　output　power　of　2kW　was　used　to　weld　brass　and　copper.　Due　to　the　high　reflectivity　and　thermal　conductivity,　laser　welding　of　copper　and　its　alloys　becomes　a　challenging　task.　The　results　of　laser　penetration　experiment　show　that　it　is　easy　to　achieve　penetration　in　laser　welding　of　brass.　In　our　experiment,　overlap　joint　with　brass　positioned　on　top　of　copper　was　adopted.　Through　optimizing　welding　parameters,　seams　with　good　formations　were　obtained.　The　characterizations　of　seam　were　observed　by　optical　metallographic　microscope,　and　the　mechanical　property　of　the　joint　was　assessed　by　bursting　test.