NOVELTY - Preparing a dye-sensitized solar cell involves preparing a semiconductor electrode (10), preparing a counter electrode (20), and charging an electrolyte (30) between the two electrodes. The preparation of the semiconductor electrode involves: preparing metal oxide dispersion; electrospraying the metal oxide dispersion on conductive substrate; thermal-pressing the conductive substrate coated with the metal oxide nanoballs at temperature of 50-200 degrees C under pressure of 0.1-25 tons per 100 cm2; and conducting the absorption of dye on the metal oxide nanoball layer.    USE - For preparing a dye-sensitized solar cell (claimed).    ADVANTAGE - The method provides a high-efficiency dye-sensitized solar cell which exhibits excellent photoelectric properties even when a gel electrolyte or solid electrolyte is used; has a high dye adsorptivity and an excellent electron transport ability due to a mesoporous metal oxide nanoball layer which is composed of agglomerated metal oxide nanoparticles and has a high specific surface area.    DETAILED DESCRIPTION - Preparing a dye-sensitized solar cell involves preparing a semiconductor electrode (10), preparing a counter electrode (20), and charging an electrolyte (30) between the two electrodes, where the preparation of the semiconductor electrode involves: preparing metal oxide dispersion by dispersing metal oxide nanoparticles in an organic solvent (0.01-5 wt.%), without any added organic binder; electrospraying the metal oxide dispersion on conductive substrate (21) to form metal oxide nanoballs having an average diameter of 50-3000 nm and specific surface area of 70-300 m2/g which are agglomerated metal oxide nanoparticles disposed on the conductive substrate; thermal-pressing the conductive substrate coated with the metal oxide nanoballs at temperature of 50-200 degrees C under pressure of 0.1-25 tons per 100 cm2, which is heat-treated at temperature of 100-700 degrees C to prepare a metal oxide nanoball layer (13) formed on the conductive substrate; and conducting the absorption of dye on the metal oxide nanoball layer.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a cross section of a dye-sensitized solar cell.    Semiconductor electrode (10)    Metal oxide nanoball layer (13)    Counter electrode (20)    Conductive substrate (21)    Electrolyte (30)