A laser uses amplified & stimulated radiation of light. Laser machine is a device which is used to generate & amplifies light. Laser stands for Light Amplification by Stimulated Emission of Radiation. Laser machine is an electrical-optical device that produces coherent radiation. Simply put, a laser is a device that creates and amplifies a narrow, intense beam of coherent light. This paper reviews some of the experimental investigates different process parameter like cutting speed, laser power, gas pressure, pulse frequency on hardox 400 material. Then the CO2 laser cutting experiment was made by using 8 mm thickness hardox 400 material. In this experiment work it is focused to establish relation of different process parameter on cut quality, which is decided by the surface roughness, kerf width, and perpendicularity.