The invention discloses a process for efficiently synthesizing dimethyl diphenyl methane. Toluene and formaldehyde are used as raw materials; under the effects of heteropoly acid and composite catalysts, the toluene and the formaldehyde take a liquid phase condensation reaction to produce dimethyl diphenyl methane, wherein the mol ratio of the toluene to the formaldehyde is 1:1 to 6:1. The process for efficiently synthesizing dimethyl diphenyl methane has the advantages that a composite catalyst and a heteropoly acid catalyst are used; high activity and repeated use activity are realized; the process belongs to an environment-friendly and efficient dimethyl diphenyl methane synthesis process. The composite catalyst and the heteropoly acid catalyst are used for catalyzing the synthesis of the dimethyl diphenyl methane, the product yield can be effectively improved; meanwhile, the temperature and the time of the synthesis reaction are reduced; the reaction speed is effectively accelerated; in addition, the raw material cost is low; the raw materials can be easily obtained; the raw materials are nontoxic and more eccentric and achieve the environment-friendly effect. The process for efficiently synthesizing the dimethyl diphenyl methane has the advantages that the synthesis process is simple; the production cost is low.