In　the　present　study,　application　of　cold　gas　spraying　technology　(CGS)　for　deposition　of　braze　filler　coatings　is　investigated.　Pure　copper　coating　were　deposited　on　magnesium　alloy　AZ31B　substrate　by　CGS.　Then　coated　magnesium　samples　were　joined　to　AISi　1008　steel　in　vacuum　furnace　by　contact　reaction　brazing　(CRB)　process.　The　microstructure　of　coated　and　brazed　samples　was　investigated.　The　experimental　results　proved　the　feasibility　of　using　cold　spraying　coatings　as　filler　interlayer　for　precision　brazing.　Cold　spraying　performed　well　due　to　the　low　thermal　impact　on　the　copper　powder　and　the　magnesium　substrates　with　low　oxygen　content.　The　bonding　temperature　influenced　the　dissolution　of　Cu　coatings,　as　well　as　the　eutectic　reaction　between　Cu　coating　and　magnesium　substrate.　The　initial　thickness　of　Cu　coatings　was　50pm　while　the　brazed　seam　has　a　thickness　of　300pm　after　eutectic　reaction.　Within　a　certain　range,　the　shear　strength　of　brazed　joints　showed　a　trend　of　increasing　firstly　and　then　decreasing　as　the　heating　temperature　increased.　Maximum　shear　strength　37MPa　was　gained　at　brazing　temperature　of　530°C　and　holding　time　of　60　min　for　brazed　joint.　Intermetallic　phases　and　interfacial　defects　such　as　microcracks,　unmelted　coatings,　overheated　compounds　were　responsible　for　the　low　strength　of　the　joints.