Excimer　lasers　can　be　applied　to　the　micro-channel　processing　on　the　Polymethyl　Methacrylate　(PMMA)　material.　PMMA　is　known　as　a　main　material　for　the　polymer　biochips　and　shows　a　property　of　the　good　absorptivity　on　the　excimer　laser.　In　this　paper,　a　Self-developed　excimer　laser　zoom-lens-processing-system　is　applied　to　process　the　continuous　variance　width-transformation＇s　mirco-channel　on　PMMA.　Firstly,　the　roughness　of　processed　zone　on　PMMA　samples　are　studied　vs　different　sample　translation　speed　and　excimer　laser　energy　respectively.　Secondly,　the　relationship　between　the　lens　group　zoom　ratio　and　the　width　of　the　micro-channel　is　discussed.　And　possible　improvements　for　the　qualities　of　processing　smoothness　are　further　discussed　based　on　the　analysis　of　the　relationship　between　the　smoothness　of　mirco-channel＇s　edge　and　the　processing　speed.