As non-metallic materials have strong absorption of long-wave infrared laser, the CO2 laser is often used to prepare PMMA micro-channels. Due to the Gaussian distribution of the laser light intensity, the cross-section of the micro-channels prepared by the conventional method is triangular. This can′t meet the practical application requirements in the microfluidic chip. In this paper, a CO2 laser multi-path translational method was proposed, which used the HAZ formed by the first etching as a boundary multi-pass lateral overlap translation etching, so that high quality micro-channels with ideal trapezoid cross section can be quickly prepared. In addition, the micro-channel fabricated in this way is smoother and more practical compared with the static multi-pass method in cross-section, HAZ, surface roughness.