A method is disclosed for making a thin-film poly-crystalline silicon solar cell. In the method, there is provided an ITO-glass substrate by coating a glass substrate with a transparent and conductive ITO film. An amorphous silicon film is grown on the ITO-glass substrate. An aluminum film is grown on the amorphous silicon film. The aluminum film and the amorphous silicon film are annealed and therefore converted and interchanged into an aluminum-silicon alloy film and a p+ poly-crystalline silicon film, respectively. In a low-temperature plasma-based deposition process, a p− poly-crystalline silicon film is coated on the p+ poly-crystalline silicon film, and an n+ poly-crystalline silicon film is coated on the p− poly-crystalline silicon film. An ohmic contact is provided on the transparent and conductive ITO film. Other ohmic contacts are provided on the n+ poly-crystalline silicon film. An anti-reflection film is coated on the n+ poly-crystalline silicon film.