In order to investigate the melting mechanism between CO2 laser and Polyamide materials, the melting experiment of PA 12 was carried out by low-power CO2 laser with static or scanning way under room temperature, and the morphology of melted samples have been examined by means of light microscopy, scanning electron microscopy (SEM) and X-ray Diffraction (XRD), meanwhile, the effect of laser irradiation method and process parameters to melting samples was analyzed. It can be seen that the melting of sample was not obvious with beam 2 mm and power ＜ 1 W, while experimental samples were got pyrogenic ablation with laser power ＞3 W during irradiating, so power intensity 0.32 W/mm2 is the sample melting threshold. The surface of samples can be melted by static irradiation, while melting depth of samples will increase with the increased laser power and scanning times, and the crystalline of melted samples have obviously improved after irradiation. The results of experiment were in good agreement with theoretical research, which will provide guidance for Polyamide materials micro-processing by CO2 laser.