Ceramic substrates are the most commonly heat dissipation substrates used for high-power LED Ceramic is a brittle material, cracks occur often during the maching process. This study used CO2 laser assisted by gas to process alumina and aluminum nitride ceramic substrates. Assisted gas flow rate and laser power were adjusted to reach high maching quality for laser scribing, drilling and cutting. In addition, cupper plating process on the surface of holes of ceramic substrates is necessary for the application to the LED. Holes with less tapered angle may obtain high quality of cupper plating. In this study, circle cutting process was used to replace the drilling process. Different laser power were tested to acquire better tapered angle.