The invention relates to a preparation method for a large-area single-layer tungsten disulfide film based on atmospheric pressure chemical vapor deposition and a product. The preparation process comprises SiO2/Si substrate cleaning, spin coating of a WO3 anhydrous ethanol dispersion solution, substrate drying treatment, sample placement and tungsten disulfide film growth. By the adoption of the method, WO3 precursor is uniformly dispersed on a substrate by spin coating of the WO3 anhydrous ethanol dispersion solution, a single-ended-closed small-caliber quartz tube is placed in a quartz tube growth chamber, and the amount of S powder and WO3 precursor participating in a nucleation and film growth process is effectively controlled, so that the prepared tungsten disulfide film has the largearea, single layer and large size. The method has the beneficial effects of being quick and repeatable and is significant in preparation of the large-area single-layer tungsten disulfide film.