Optical disk drive for compensating wobble signal and method thereof

An optical disk drive for compensating wobble signal and the method thereof. The compensating method is used in a servo controller and an optical pick-up head. The optical pick-up head includes a laser diode, a photo detector and an objective lens. The servo controller includes an auto gain controller. Firstly, a beam is emitted by the laser diode emits and is focused on an optical disc to generate a reflective beam. Next, the photo detector receives the reflective beam to generate plural photo-detecting signals received by the auto gain controller to generate a first control signal and a second control signal. Then, the servo controller generates a third control signal according to the first and the second control signals. The objective lens is moved according to the third control signal. Lastly, the photo detector receives the reflective beam to generate plural calibrated photo-detecting signals whereby a wobble signal is generated.