An adjustment mechanism, comprising a left adjustment screw, a stop block threadedly connected to the left adjustment screw, and a right adjustment screw, also comprised are a sliding block a side surface of the front end of which is provided with a transverse sliding groove, a transverse mounting block having an LED chip module mounting base, and a wedge-shaped block; a limiting pin and a spiral reset spring sleeved on the limiting pin are provided at the end part of the right end of the transverse mounting block; the right adjustment screw is threadedly connected to a vertical side surface of the wedge-shaped block, a mounting groove for mounting the LED chip module mounting base is provided at the top part of the transverse sliding block, and a front end extending surface of the mounting groove communicates with the transverse sliding groove.