NOVELTY - High-purity chalcogenide powder is mixed with a solvent, viscosity modifier is added and stirred, to obtain stable precursor solution. A bottom electrode and metal or metal chalcogenide reactive layer are sequentially formed on a substrate, and chalcogenide solution is coated on reactive layer, to obtain cured film of chalcogenide. The resultant product is vacuum-sealed high-temperature furnace, heated, and buffer layer of metal chalcogenide is formed on resultant product, and window layer and electrode material is formed on buffer layer, to obtain chalcogenide thin film solar cell.    USE - Preparation of chalcogenide thin film solar cell (claimed).    ADVANTAGE - The method enables economical, easy and efficient preparation of nontoxic chalcogenide thin film solar cell having large area.    DETAILED DESCRIPTION - High-purity chalcogenide powder having purity of 99.99% chosen from sulfur and selenium is mixed with solvent chosen from ketone, alcohol, amine and organic solvent, viscosity modifier is added and stirred at room temperature for more than 12 hours, to obtain stable precursor solution. The concentration of chalcogenide in solution is adjusted to 0.01-5 M by adding or reducing the solvent. A bottom electrode chosen from molybdenum, titanium and transparent conductive oxide is formed on a substrate chosen from glass, rigid and flexible metallic material and polymeric film using high-vacuum gas-phase process including thermal evaporation, magnetron sputtering and molecular beam epitaxy. A metal or metal chalcogenide reactive layer having thickness of 0.6-2 mu m is formed on the bottom electrode using high-vacuum gas-phase process including thermal evaporation, magnetron sputtering and molecular beam epitaxy. The high-purity chalcogenide solution is coated on metal or metal chalcogenide reactive layer by spray deposition, ink jet printing, die coating or knife coating at ambient temperature, and baked at low temperature, to obtain cured film of chalcogenide. The resultant product is vacuum-sealed in high-temperature furnace, uniformly heated at 200-1000 degrees C, processed for 5-60 minutes and reactive layer is completely converted into polycrystalline chalcogenide semiconductor thin film. Then, a buffer layer of metal chalcogenide is formed on polycrystalline chalcogenide semiconductor thin film by chemical bath deposition. Then, a window layer and electrode material is formed on buffer layer using high-vacuum gas-phase process including thermal evaporation, magnetron sputtering and molecular beam epitaxy, to obtain chalcogenide thin film solar cell. The metal of metal or metal chalcogenide reactive layer is chosen from copper, zinc, tin, indium and gallium. The metal of metal chalcogenide in buffer layer is chosen from cadmium and zinc. The window layer comprises metal chalcogenide in which metal is zinc. The electrode material is chosen from molybdenum, titanium and transparent conductive oxide.