A method for preparing zirconium boride and synchronously preparing a cryolite is provided which includes the following steps: Step A: placing aluminum in a reactor, heating the reactor to 700-850 degrees centigrade, and adding the mixture of fluorozirconate and fluoborate; and Step B: stirring the reactants for 4-6 hours and extracting the upper molten liquid to obtain a cryolite, wherein the lower substance is zirconium boride. The disclosure has the following beneficial effects: the new zirconium boride preparation method provided herein is simple in preparation flow and the device used, short in preparation period and high in reaction efficiency, the prepared zirconium boride with many contact angles has a large specific surface area and contains a controllable amount of aluminum.