A method of transferring a thin film includes: providing a first element structure, wherein the first element structure includes a first substrate and a functional film layer formed on the first substrate; completely removing the first substrate, wherein steps of the completely removing the first substrate includes: conducting an etching step to erode the first substrate, and conducting a grinding step to planarize the eroded first substrate; and after completely removing the first substrate, attaching the functional film layer on a second substrate to form a second element structure. |