A laser system (99) for patterning a mold insert includes a laser source module (10), a feedback module (20), and a controlling module (30). The laser source module includes a laser source (11) for emitting laser beams, and a lens module (10) with a changeable focal length configured for focusing the laser beams on the surface of the mold insert. The feedback module (20) is configured for receiving the laser beams reflected from the surface of the mold insert and generating a corresponding feedback signal according to the received laser beams. The controlling module is configured for receiving the feedback signal from the feedback module thereby controlling the laser source according to the feedback signal. A method for manufacturing the mold insert is also provided.