We　studied　the　microstructure　characteristics　and　solidification　behaviour　of　the　recast　layer　on　a　1　mm　Al2O3　electronic　ceramic　substrate　processed　by　CO2　laser　cutting　to　improve　the　cutting　quality.　SEM　(scanning　electron　microscope)　and　CLSM　(confocal　laser　scanning　microscope)　observations　showed　that　the　upper　and　lower　regions　of　the　recast　layer　consist　of　equiaxed　grains,　while　columnar　grains　dominate　in　the　middle　region,　downgrading　cutting　quality.　We　used　finite　element　modelling　(FEM)　to　understand　the　solidification　mechanism　and　explain　profile　and　microstructure　variation　along　the　kerf.　Using　this　analysis,　we　performed　experiments　to　study　the　influences　of　assist　gas　pressure　and　laser　cutting　speed　on　the　grain　size　and　recast　layer　thickness.　A　thin,　dense　recast　layer　of　uniform　thickness　and　microstructure　resulted　from　the　following　optimal　parameters:　8　bar　N-2　assist　gas　pressure,　cutting　speed　of　1500　mm/min,　and　laser　fluence　of　200W.　(C)　2012　Elsevier　Ltd.　All　rights　reserved.