This　article　describes　high　beam　quality　and　kilowatt-class　diode　laser　system　for　direct　materials　processing,　using　optical　design　software　ZEMAX　(R)　to　simulate　the　diode　laser　optical　path,　including　the　beam　shaping,　collimation,　coupling,　focus,　etc..　In　the　experiment,　the　diode　laser　stack　of　808nm　and　the　diode　laser　stack　of　915nm　were　used　for　the　wavelength　coupling,　which　were　built　vertical　stacks　up　to　16　bars.　The　threshold　current　of　the　stack　is　6.4A,　the　operating　current　is　85A　and　the　output　power　is　1280W.　Through　experiments,　after　collimating　the　diode　laser　beam　with　micro-lenses,　the　fast　axis　BPP　of　the　stack　is　less　than　60mm.mrad,　and　the　slow-axis　BPP　of　the　stack　is　less　than　75mm.mrad.　After　shaping　the　laser　beam　and　improving　the　beam　quality,　the　fast　axis　BPP　of　the　stack　is　still　60mm.mrad,　and　the　slow-axis　BPP　of　the　stack　is　less　than　19mm.mrad.　After　wavelength　coupling　and　focusing,　ultimately　the　power　of　2150W　was　obtained,　focal　spot　size　of　1.5mm　*　1.2mm　with　focal　length　300mm.　The　laser　power　density　is　1.2x10(5)W/cm(2),　and　that　can　be　used　for　metal　remelting,　alloying,　cladding　and　welding.　The　total　optical　coupling　conversion　efficiency　is　84%,　and　the　total　electrical　-　optical　conversion　efficiency　is　50%.