The invention provides a synthesis method of 2-bromo-9,9-diphenylfluorene and belongs to the technical field of organic synthesis. The synthesis method comprises steps as follows: (1), after 2-bromo-9-phenyl-fluorene-9-ol and benzene are mixed, reaction gas is introduced for a reaction at the temperature of 61-66 DEG C while the components are stirred, the temperature is increased and backflow is performed after gas introduction is finished, and water is separated while backflow is performed; (2), a catalyst is added in 0.5-1 h after a system obtained from the step (1) is cooled, the temperature is increased to 35-50 DEG C, and the mixture reacts for 3.5-5 h; (3), 2-bromo-9,9-diphenylfluorene is obtained through separation and purification. The synthesis method of 2-bromo-9,9-diphenylfluorene is low in cost, especially when hydrogen chloride and hydrogen bromide are utilized; with the adoption of an aluminum trichloride anhydrous and ferric chloride anhydrous mixed catalysis mode, the catalysis effect is good, the reaction time is short, and the yield is high; the operation is simple, the process is reliable, and scale-up is facilitated.