Method of forming cutting portions or removal portions of printed substrate using laser processing capable of preventing processing powder or steam from attaching on printed substrate surface and thus avoiding malfunction of electric devices mounted thereon

The present invention provides a method of forming cutting portions or removal portions of printed substrate using laser processing, which includes: setting a target processing line at a designed position of a printed substrate for displaying the shape of a cutting portion matched with the designed size; setting a plurality of auxiliary processing lines based on the target processing line; and, sequentially irradiating these auxiliary processing lines with the laser beam toward the target processing line to form a plurality of grooves, wherein the grooves are formed with a plurality of tapered surfaces, and the overlapping range of the adjacent tapered surfaces is set to be equal to a translation amount. By repeatedly performing the aforementioned laser processing and while discharging the processing powder or steam from one side of the cutting portion, the printed substrate will be cut out and the cutting surface of the printed substrate may be smooth, such that the cutting portion of the printed substrate m