The invention discloses a device and method for improving the processing quality of holes with arbitrary angles by changing the laser incident angle, and relates to the field of laser drilling, including a base, a left positioning support plate, an angle control rotating shaft, a workpiece clamping device, bolts, telescopic Clamping device, right positioning support plate, support shaft, rotating shaft, rotating guide rail, gears, positioning fixing bolt holes and rotation unit; the base angle control unit passes through the center of the left support plate and is fixed on the positioning support plate, and the right side is retractable clamp The unit cooperates with the left side to clamp multi-size workpieces. The angle rotation unit is used to precisely adjust the corresponding angle. After the hole machining position is determined, the rotation speed of the lower rotation unit gear is controlled to make the rotation axis rotate continuously and stably along the rotation guide rail. Let the laser have a certain incident angle to process the inner wall of the hole, better remove excess material, improve the processing quality of the inner wall and reduce the taper.