The　slow-axis　of　a　high　power　diode　laser　stack　is　collimated　and　focused　by　a　telescope　system　that　consisted　of　two　pieces　of　cylindrical　lens.　The　stack　is　consisted　of　five　diode　laser　array　each　power　is　60　W,　and　the　central　wavelength　is　808　nm.　We　test　the　waist　sizes　of　the　beam　in　the　system　consisted　of　different　lenses,　and　study　the　affection　of　the　cylindrical　focal　length　on　it.　Beam　paths　of　the　telescope　system　are　simulated　by　Zemax　software,　and　the　system　aberration　is　analyzed.　When　the　slow-axis　collimating　focal　length　is　200　mm,　the　focusing　length　is　100　mm,　we　can　get　the　laser　power　density　at　3.05　kW/cm2.　Under　these　experimental　conditions,　the　irradiation　test　of　316L　stainless　steel　is　conducted,　vaporized　groove　is　found　on　the　plate　and　depth-to-width　ratio　is　about　0.5.