The invention discloses a quaternary thioarsenate compound semiconductor material as well as a preparation method and an application thereof. Alkaline earth metal hydroxide, metallic silver, binary solid solution As2S3 and elementary substance S are taken as raw materials, hydrazine hydrate is taken as a solvent, the mixture reacts in a drying oven at the temperature of 160 DEG C for 4-7 days, and the quaternary chalcogenide semiconductor material is obtained. The chemical composition formula is BaAgAsS3 and SrAg4As2S6*H2O. The quaternary thioarsenate compound semiconductor material as well as the preparation method and the application thereof have the advantages that the operation process is simple, raw materials are simple and low in cost, the reaction condition is mild, the synthesis temperature is low and the like. The quaternary chalcogenide has the yield of up to 50%, is high in chemical purity and is used for preparing optical semiconductor devices or solar cell transition layer materials.