The invention discloses a preparation method for a doped leucinol rust inhibitor, and belongs to the field of chemical building materials. The doped dimethylaminoethanol reinforced concrete liquid type rust inhibitor is prepared by using L-leucinol, water, an orthovanadate, mercaptobenzothiazole, sodium tripolyphosphate and sodium polyacrylate as raw materials and through a method of mixing the raw materials at a specific temperature. The preparation method is simple in process, low in production cost and good in product quality. The doped leucinol rust inhibitor is simple in usage method and is suitable for being added into various concretes for common industrial and civil buildings. After the doped leucinol rust inhibitor is used, the concrete has a good rust-inhibiting effect. Besides, the doped leucinol rust inhibitor is low in cost and small in toxicity, and has no influence on physical health of operation staffs who are engaged in concrete constructions.