The invention discloses a flexible dye-sensitized solar cell and a preparation method thereof. The flexible dye-sensitized solar cell comprises a first electrode, a second electrode, electrolyte arranged between the first electrode and the second electrode and dye sensitizing agent. The first electrode is composed of a PET provided with transparent conductive film and a platinum electrode layer formed on the PET. The second electrode is composed of a Ni-W substrate, a conductive layer formed on the Ni-W substrate, a block layer formed between the Ni-W substrate and the conductive layer and a nano porous layer which is formed on the conductive layer and back on to the block layer side. The preparation process of the flexible dye-sensitized solar cell includes: A, preparation of the block layer; B, preparation of the conductive layer; C, preparation of the nano porous layer; and D, packaging of the flexible dye-sensitized solar cell. The Ni-W substrate is adopted as working electrode, so as to realize flexible design of dye-sensitized solar cell. And meanwhile, the block layer is deposited on the Ni-W substrate, thus effectively improving photoelectric conversion efficiency of flexible dye-sensitized solar cell.