The present invention discloses an XY platform device with nanoscale precision including an optical pickup head for focusing and seeking the tracks of an optical data storage medium; a servo device for driving the optical pickup head to move in focusing and radial directions; a carrier platform for receiving a testing object thereon and providing a connecting member to be connected with the optical pickup head. With the focusing and radial movements of the optical pickup head, the carrier platform is driven to move accordingly, and thus achieving the high-precision and low-cost effects.