A thin film transistor includes an active layer, a first loose layer and a first oxygen release layer. The first loose layer is at least disposed on a first surface of the active layer perpendicular to a thickness direction of the active layer, and is in contact with the active layer. A material of the first loose layer includes a first inorganic oxide insulating material. The first oxygen release layer is disposed on a surface of the first loose layer facing away from the active layer, and is in contact with the first loose layer. A material of the first oxygen release layer is a first oxygen-containing insulating material. A porosity of the first loose layer is different from a porosity of the first oxygen release layer, and/or an oxygen content of the first loose layer is different from an oxygen content of the first oxygen release layer.