Disclosed herein is a method for preparing 4,4'-dinitrodiphenylamine, comprising reacting urea and nitrobenzene in a polar organic solvent in the presence of a base at a temperature of room temperature to 1000 °C. The method employs a relatively cheap urea and nitrobenzene as the raw materials, and also employs a relatively cheap base, thereby decreasing the manufacturing costs. Moreover, the method does not produce by-products, thus eliminating a need for a post-treating process. Additionally, the method is advantageous in that the production of 4,4'-dinitrophenylamine can be achieved in high yield and selectively even under non-intensive reaction conditions by appropriately controlling the amounts of urea and nitrobenzene.