Signiˆcant progress in recent development of synchrotron radiation (SR) sources has oŠered the opportunity for time-resolved Xray diŠraction studies of fast lattice dynamics in the atomic scale. The coherent atomic motion, as seen in coherent optical and acoustic phonons which are induced by femtosecond pulsed laser irradiation of semiconductor surface has directly been observed with the timeresolved X-ray diŠraction technique. In this article, the time-resolved diŠraction methods using an SR beam are summarized, and the demonstrations for acoustic pulse echo, coherent acoustic phonon, and optical phonon are reviewed as examples of the investigation on coherent lattice dynamics. The future prospective on the investigation of lattice dynamics using time-resolved X-ray diŠraction experiments is also discussed.