The invention provides a method for synthesizing 3,4,5-trifluoro-2'-nitrobiphenyl; a synthetic route is as shown in the description, wherein -X represents a substituent group selected from one of -Cl, -Br, -I, COOH, -N2Cl and -N2HSO4. The method comprises the following steps of (1), dissolving the raw materials including 3,4,5-trifluorobenzeneboronic acid and ortho-nitro substituted benzene in a solvent, and adding a catalyst and an acid-binding agent; (2), reacting while stirring till finishing; (3), washing, and extracting to obtain an organic phase; and (4), concentrating, and recrystallizing to obtain 3,4,5-trifluoro-2'-nitrobiphenyl. According to the invention, the Ms-Pd catalyst having high catalytic activity is adopted; furthermore, multi-batch indiscriminate use can be realized; and the method is high in yield, high in product purity, convenient to postprocess and environment friendly.