In order to study the laws of single- or double-layer metal/polyimide etched by movable pulse lasers, one general model of movable nanosecond pulse laser etching is built with the finite element method. The influence of laser movement speed on etching depth is discussed, and the law of temperature change of the metal Al thin films and double-layer metal thin films etched by movable pulse laser is analyzed. The results show that, with a certain movement speed, the etching depth increases at the beginning, then the increase rate slows down, and the etching depth approaches to one constant maximum value. The temperature change at the interface between the metal and the substrate material lags behind that of the metal thin film close to laser source, and the substrate temperature rises continually after turning off the laser. As for double-layer metal films, the choice of thicker bottom layer with a high thermal conductivity is helpful to protect the polyimide substrate.