The invention discloses a composite acid supported catalyst and a catalytic synthesis method of bisphenol F. A synthesis method of the composite acid supported catalyst comprises the following steps: adding phosphoric acid, diatomite, LiCl and titanium dioxide to ethanol according to a certain ratio, and refluxing and stirring above raw materials overnight (for 12-24h); and recovering ethanol after the above reaction ends, washing the obtained material with water 3 times, and carrying out vacuum drying for 12h to obtain the composite acid supported catalyst. The synthesis method of bisphenol F comprises the following steps: adding phenol and the composite acid catalyst to a reaction container, adding xylene, stirring above materials at room temperature, adding 37% of an aqueous formaldehyde solution in a dropwise manner, and heating the obtained solution to 100-150DEG C, wherein the temperatures are 100DEG C, 125DEG C and 150DEG C respectively, toluene is adopted as a solvent, and the reaction time is 2-8h; and recovering the catalyst, the solvent and phenol, and re-crystallizing the above obtained product with the recovered solvent to obtain pure bisphenol F. The catalyst has the advantages of increase of the bisphenol F yield, simple synthesis method, low cost, high catalysis activity and reusability.