Auto alignment system, which is used for beam adjustment in high power laser driver system, is not only the key subsystem ensuring the routine operation effectually and safely, but also the main method to ensure the beam quality. An Ethernet local area network (LAN) is built and digital CCD is used for beam image acquisition and transmission, so that image data can be directly converted into digital signals and output via Ethernet to computer. Gaussian smoothing filter algorithm is used to improve the accuracy of image processing, while fuzzy algorithm is applied to the motor control process which can shorten the alignment time. The experiment is completed on No.9 system of SG-II laser facility. Experimental results show that all adjustments of alignment are finished within 5 min and the accuracy of image acquisition and processing can be up to 1 pixel.