Abstract: The temperature fields of aluminum, magnesium and titanium irradiated by laser are calculated by using the self-developed program LAMP, in which the effect of the laser mode on the ablation is mainly analyzed, while the relation between the reflectance and the temperature is taken into account. The calculated results show that the smaller the repeated frequency and the duty ratio are, the shorter the time to ablate the metal sheet will be at a same average laser power and a same thickness of the metal.