An effective method is proposed that enables one to simultaneously analyze details of numerous holographic grating patterns over a large area. Unlike the conventional approaches relying on sophisticated lighting and optical systems and dark environment, only a flatbed scanner is needed. Thanks to the “rotate-scan” measurement strategy, details of the holographic grating patterns can be obtained, e.g., spatial distribution of the grating patterns, interval and orientation of the grating grooves within each grating pattern, and defects of the holographic patterns. The method has been verified by applications to two holographic papers of different grating intervals and orientations. The measured values agree well with those obtained with a light optical microscope (LOM). The proposed method is applicable to both transparent and reflective holographic materials of broad grating periodicity.