Abstract: A manufacturing method of an optical device includes: providing a lower transparent substrate; wherein the lower transparent substrate includes an upper surface; providing a quantum dot film element and a glue-material enclosure wall disposed on the upper surface; wherein the glue-material enclosure wall surrounds the quantum dot film element; providing an upper transparent substrate covering the quantum dot film element and the glue-material enclosure wall, such that the quantum dot film element and the glue-material enclosure wall are sandwiched between the lower transparent substrate and the upper transparent substrate; and cutting the lower transparent substrate and the upper transparent substrate to form a lower protective film and an upper protective film corresponding to the quantum dot film element, so as to obtain the optical device including the lower protective film, the upper protective film, the quantum dot film element, and the glue-material enclosure wall.