Abstract: The spot array is indispensable for optical computing,ortical interconnection and photo switching network. All of the systems require high spot uniformity of the array. Therfore,the diagnosis ofthe spot array is very important. In our dignostic system,a CCD sensor is used as a detector. The experimental results show that the system is effective in mearuring of the relative characteristics of the largespot array. As a example,the test results to 8×8and 32×32 array are inteduced in this paper.