The present invention discloses an adjusting mechanism of guide rod for an optical disk drive. The adjusting mechanism includes at least a guide rod for supporting an optical pickup head, an adjusting member and an elastic member. The adjusting member is set to be adjacent to the guide rod, and the elastic member provides elasticity to the guide rod to press the guide rod on a side surface of the adjusting member. The guide rod is moved to be close or away from a spindle motor by the adjusting member and in turn to adjust the off-center distance between the spindle motor and a laser beam emitted from the optical pickup head to improve the reading accuracy and efficiency of the optical pickup head.