The present invention discloses a method for preparing 1,2-diphenylethane. The method comprises the following steps that: iron powder is added into a water phrase to compound a catalyst of copper and react with benzyl chloride to produce the 1,2-diphenylethane; 1,2-diphenylethane is obtained after undergoing acid washing, water washing, alcohol washing, distilling, and slicing. With the method, the copper powder only needs to be added at once, and can be circularly used for a plurality of times. The repeated addition of the costly copper and cuprous chloride is not required and the reaction goes smoothly to give products meeting expection. Further, the method is low in the manufacturing cost and safe. The corrosion to equipment during the reaction process is light. The cuprum can be circularly used, and thus the manufacturing cost of 1,2-diphenylethane is reduced.