Aiming at the problem of precise alignment of industrial arm, an industrial robot alignment method based on monocular vision is proposed. Combining the industrial robot with monocular vision measurement and a specialized hand-eye calibration panel, the method is able to quickly establish the hand-eye relationship between the camera coordinate system and the alignment axis on the robot's end-effector. In the alignment stage, the attitude of the workpiece is obtained by monocular vision system, and then according to the existing hand-eye relationship and datum posture, the position and orientation between the alignment axis and the workpiece of the alignment axis are evaluated. The experimental results show that the average precision of the alignment is better than 0.2° under the measuring distance of 150 mm.