Facing　the　problems　of　high　thermal　resistance　and　high　temperature　difference　on　the　top　surface　of　semiconductor　laser　arrays＇　directional　macro-channel　liquid-cooled　heat　sinks　inducing　different　lifetimes　and　hard　controlling　of　spectral　width,　the　temperature　distribution　of　internal　heat　sinks　through　the　finite　element　modeling　is　presented.　The　heat　sink　under　consideration　is　made　of　copper　with　varying　the　area　of　coolant　inlet.　Established　analysis　and　simulation　models　show　that　a　heat　sink　with　smaller　inlet　area　provides　a　lower　surface　temperature　gradient　and　a　better　capability　of　heat　dissipate.　A　continuous　wave　(CW)　120　W　output　semiconductor　laser　arrays　pump　source　(3　laser　bars)　is　obtained　by　using　this　kind　of　small　inlet　macro-channel　heat　sink.　The　central　wavelength　is　807.7　nm　with　a　full　wavelength　at　half　maximum　(FWHM)　of　2.8　nm.