An　improved　microfabrication　method　was　used　to　fabricate　a　continuous-flow　PCR　(polymerase　chain　reaction)　microfluidic　chip　on　the　PMMA　substrate　using　the　low-power　CO2　laser　ablation　technique.　The　use　of　the　low-power　CO2　laser　and　the　PMMA　material　could　reduce　the　cost　and　the　time　of　the　fabrication　process,　especially　at　the　step　of　laboratory　research　because　of　the　high　flexibility　of　the　laser　fabrication　technique　and　the　low　cost　of　PMMA.　A　CO2　laser　output　power　of　4.5　W　and　a　laser　scanning　velocity　of　76.2　mm/s　were　chosen　to　fabricate　the　chip　in　this　work.　The　micromachining　quality　could　satisfy　the　microfluidic　requirement　of　the　PCR　mixture　within　the　microchannel.　Good　temperature　distribution　and　gradient　were　obtained　on　the　PMMA　chip　with　a　home-built　integrated　heating　system.　An　amplification　of　DNA　template　with　a　990　base　pair　fragment　of　Pseudomonas　was　successfully　performed　with　this　chip　to　characterize　its　availability　and　performance　with　various　flow　rates.