A laser beam is split into several sub-beams, each of which has different delay time and is encoded by using a grating placed in different azimuth. After converging by means of a series of reflectors, these sub- beams become one beam again which is used to diagnose the object through holographic interference and holographic shadowgraph. When the hologram is decoded, a set of interference patterns or shadowgraphs corresponding to different moments can be obtained.