The disintegration process of a radial liquid sheet due to laminar-turbulent transition is investigated by LDV measurement. Radial liquid film flow is generated by a water discharge through a small gap formed between the end of a nozzle and the flat surface of a disk. The liquid film flow spreads radially on the disk, flowing from the disk edge into the still air as a liquid sheet. Sudden laminar-turbulent transition occurs in the liquid sheet when the Reynolds number exceeds a critical value, resulting in the perforation and the disintegration of the liquid sheet: the configuration of the liquid changes from the liquid sheet into ligaments and drops in the disintegration process. In order to identify the liquid configuration, a laserbeam through the liquid sheet is detected using a photo sensor. LDV measurement synchronized with photography and photo-sensing reveals that while small drops are formed as satellite drops at low Reynolds number, they are done by separations from microprojections, which exist on the ligaments and the edges of perforations, at high Reynolds number.