Disclosed are a viewing angle adjustment film structure, a manufacturing method thereof, and a display device, including a base, an isotropic optical material layer, and a liquid crystal layer stacked in sequence. The isotropic optical material layer is provided with grooves, the liquid crystal layer fills the grooves, and light enters from the liquid crystal layer and then exits through the isotropic optical material layer. Director of liquid crystal molecules in the liquid crystal layer is changed according to an external applied voltage or a change of an electric field, so as to adjust a viewing angle of the light emitted from the isotropic optical material layer.