The present disclosure discloses a thin film package structure, a thin film packaging method and a display device. The thin film package structure includes: an inorganic layer, a buffer layer and an organic layer successively covering an external of an electroluminescence unit structure from inside to outside; composition of said buffer layer is organic, and a thickness of said buffer layer is less than that of said organic layer. The thin film packaging method includes: covering a buffer layer on an inorganic layer encapsulating an electroluminescence unit structure; covering an organic layer on a surface of said buffer layer; composition of said buffer layer is organic, and a thickness of said buffer layer is less than that of said organic layer.