Laser　marking　has　been　found　wide　application　in　many　fields.　However,　laser　colorful　marking　has　seldom　been　used　because　of　its　complexity　of　processing.　Recently,　the　researchers　have　been　attracted　on　this　research　for　its＇　huge　potential　market.　Nevertheless,　the　mechanism　of　laser　colorful　marking　is　still　not　quite　clear.　In　order　to　explore　essence　of　laser　colorful　marking　on　metal,　this　paper　introduces　the　mechanism　of　laser　colorful　marking　on　stainless　steel　and　titanium　and　the　mechanism　of　color　generation　of　film　processed　by　laser　colorful　marking.　The　mechanism　of　laser　colorful　marking　on　metal　is　the　optical　films　which　are　oxide　and　nitride　coated　on　the　surface　of　metal,　are　generated　by　controlling　laser　energy　input　and　the　approach　of　scanning　region.　It　was　found　that　the　films　on　surface　of　stainless　steel　contain　ferric　oxides　and　nitrides　and　the　films　on　surface　of　titanium　contain　titanium　oxides　and　nitrides.　The　composition　of　films　with　different　color　is　different　in　terms　of　substance.　©　2009　Copyright　SPIE　-　The　International　Society　for　Optical　Engineering.