Embodiments of present disclosure relates to an apparatus and a method for calibrating a laser displacement sensor for use with a robot. The apparatus comprises an auxiliary object arranged in a work space of the robot or held by the robot and comprising a planar surface adapted to be detected by the laser displacement sensor; and a controller configured to: determine a characteristic point on the planar surface of the auxiliary object based on a detection result from the laser displacement sensor; cause the laser displacement sensor to point at the characteristic point for plural times with the same angle and different distances to obtain an orientation of the laser displacement sensor; and cause the laser displacement sensor to point at the characteristic point for plural times with different angles and the same distance to obtain a relative position relationship between the laser displacement sensor and the robot.