Abstract: The characteristic of CCD Beam Size Detector is employing a Charge Coup-ling Device (CCD) as the transducer, and Synchrolight of beam as the signalsource. The detector has both analogous output and digital output. Its measure-ment ratio is relatavely high, and it does not interrupt beam lifetime. So thisdetector is an effective device for electron and positron storage ring operationand studies.