As　diode　laser　processing　for　different　processing　technologies　demands　different　power　densities　and　spot　sizes,　this　paper　researched　how　to　get　focus　spot　outputs　with　different　sizes　by　adjusting　optical　path　design　to　meet　the　requirements　of　various　laser　applications.　By　using　ZEMAX　to　simulate　the　diode　laser　optical　path,　including　beam　shaping,　collimation,　focus,　etc.,　several　kinds　of　spot　outputs　with　various　sizes　was　implemented.　In　the　experiment,　a　980　nm　diode　laser　stack　with　the　superposition　of　16　bars　was　used　by　a　threshold　current　of　6.4　A,　the　maximum　operating　current　of　84.8　A,　maximum　output　power　of　1280　W,　and　the　total　electrical-optical　conversion　efficiency　of　58.9%.　After　collimation,　the　divergence　angles　for　the　fast　axis　and　slow　axis　are　less　than　4　mrad　and　20　mrad,　respectively.　Finally,　the　experiments　were　performed　on　the　diode　laser　stack　by　the　beam　shaping,　collimation　and　focusing,　and　a　power　output　of　1031　W　is　obtained.　Furthermore,　the　focused　spot　size　has　been　1.2　mm　×　1.5　mm　and　the　laser　power　density　is　up　to　3.8×104　W/cm2　when　the　focal　length　of　focusing　mirror　is　300　nm.　Results　show　that　the　laser　stack　can　be　used　in　remelting,　alloying,　cladding　and　thermal　conductivity-type　welding　for　metal　surfaces.