The invention discloses a dye-sensitized solar cell based on a three-element composite gel quasi-solid electrolyte and a preparation method thereof. The method comprises the steps of mixing a polymer, a nano inorganic compound and a graphene as gelling agents and a liquid iodine-based electrolyte to obtain the three-element composite gel quasi-solid electrolyte, printing the three-element composite gel quasi-solid electrolyte to the photo anode and counter electrode of the cell through a screen printing method, and finally assembling the photo anode and counter electrode with the printing of the three-element composite gel quasi-solid electrolyte together through a UV curing adhesive to form the dye-sensitized solar cell based on the three-element composite gel quasi-solid electrolyte. The preparation process of the method is simple, the excellent performance of various materials is combined, the cell assembly process is simple and quick, the assembly time can be greatly shortened, and the adequacy of the contact between the quasi-solid electrolyte and the electrode can be effectively improved.