The invention discloses a synthesis method of a benzophenanthrene dodecyl bridged perylenetetracarboxylic butyl ester binary compound discotic liquid crystal material. The synthesis method comprises the following three parts: part 1, synthesizing perylenetetracarboxylic butyl ester, and then synthesizing perylene monoanhydride monobutyl phthalate; part 2, synthesizing monohydroxy-penta hexyloxy benzophenanthrene, and then synthesizing alkoxy benzophenanthrene with one w-bromine branch; and part 3, synthesizing a benzophenanthrene dodecyl bridged perylenetetracarboxylic butyl ester binary compound through intermediates obtained in the previous two parts. The benzophenanthrene derivate is high in optical property and thermal stability; in addition, raw materials for synthesizing such compound are easily obtained, and the product is easily purified; moreover, perylene derivate biomolecules have a big conjugated system, so that the structure modification is easily carried out, and the photoelectric property is outstanding. The benzophenanthrene derivate and the perylene derivate are connected through a flexible bridge chain to form the benzophenanthrene dodecyl bridged perylenetetracarboxylic butyl ester binary compound discotic liquid crystal material. The benzophenanthrene dodecyl bridged perylenetetracarboxylic butyl ester binary compound discotic liquid crystal material can be applied to photoelectric appliance such as organic photovoltaic materials and liquid crystal materials.