The invention relates to a thin film electrode of a dye-sensitized solar cell and a preparation method thereof, the electrode comprises two layers, wherein a conductive substrate is conductive glass, the first layer is a commercial titanium dioxide electrode, the second layer is a lithium titanate coating, the thickness is 20-80 mu m, and the total thickness is 35-110 mu m. The preparation methodcomprises the following steps: adding lithium titanate particles into a solvent which takes one or mixture of a plurality of n-butanol, isopropanol, op emulsifier and naphthol as a system, wherein the weight percent of lithium titanate in the solvent is 5-15%; grinding, carrying out ultrasonic oscillation and then standing for standby; coating a layer of the lithium titanate on the surface of titanium dioxide by using the screen printing method, and drying; and placing a well coated thin film into a muffle furnace for sintering, taking out the well sintered compound thin film electrode, placing into commercially available dye sensitizing solution, soaking for 15h-24h in the dark and taking out. The method can effectively improve the open-circuit voltage of the dye-sensitized solar cell and simultaneously not affect the short-circuit current, the fill factor and other related parameters of the dye-sensitized solar cell.