NOVELTY - Thin film solar cell based on sulfur compound nanocrystal comprises metal counter electrodes, tribasic/tetrabasic sulfur compound nanocrystal light absorbing layer, titanium dioxide nanorod array, transparent conductive layer and transparent substrate, where the metal counter electrodes are gold and/or silver. The sulfur compound in the tribasic/ tetrabasic sulfur compound nanocrystal light absorbing layer is compound (I) and silver indium sulfide. The average grain size of nanocrystal is 2-12 nm.    USE - Used as a thin film solar cell based on sulfur compound nanocrystal.    ADVANTAGE - The method for preparing thin film solar cell based on sulfur compound nanocrystal: has mild reaction condition; is simple and economical; and utilizes easily available raw materials.    DETAILED DESCRIPTION - Thin film solar cell based on sulfur compound nanocrystal comprises metal counter electrodes, tribasic/tetrabasic sulfur compound nanocrystal light absorbing layer, titanium dioxide nanorod array, transparent conductive layer and transparent substrate, where the metal counter electrodes are gold and/or silver. The sulfur compound in the tribasic/ tetrabasic sulfur compound nanocrystal light absorbing layer is a compound of formula (CuInSxSe2-x) (I), where x is 0-2 and silver indium sulfide. The average grain size of nanocrystal is 2-12 nm. The diameter of the nanorod in the titanium dioxide nanorod array is 50-200 nm and the thickness of it is 1-10 mm. The gap between the nanorods is 50-200 nm. The nanorods vertically grow along the transparent substrate. The transparent substrate is glass plated with fluorine-doped tin oxide or indium tin oxide conductive layer. An INDEPENDENT CLAIM is also included for the preparation of the thin film solar cell based on sulfur compound nanocrystal, comprising: (a) dissolving the prepared tribasic/tetrabasic sulfur compound nanocrystal in an organic solvent, then coating it on titanium dioxide nanorod array, and then drying for 0.5-12 hours under the conditions of 40-150 degrees C of temperature and 0.1 MPa of vacuum degree; (b) under condition of saturated sulfur steam and argon atmosphere and 1 MPa of pressure, processing for 0.5-2 hours at 300-450 degrees C; and (c) preparing metal electrode on mixture of the titanium dioxide nanorod array and the tribasic/tetrabasic sulfur compound nanometer crystal.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the thin film solar cell based on sulfur compound nanocrystal.