The invention discloses a method for synthesizing a diaryl acetylene monomer liquid crystal, which comprises a method for performing coupling reaction between halogenated aryl hydrocarbon and aryl alkyne, wherein the reaction conditions comprise that the halogenated aryl hydrocarbon and the aryl alkyne perform the coupling reaction in an acetone/water (5:2) solvent at a temperature of between 50 and 110 DEG C, under the normal pressure and under the protection of inert gas, and a catalyst used in the reaction is Pd/C-CuI-PPh3. The halogenated aryl hydrocarbon and the aryl alkyne are added according to an equivalent weight of 1/1.1, three substances in the catalyst Pd/C-CuI-PPh3 are added according to the equivalent weight of (0.0003-0.007)/(0.006-0.05)/(0.005-0.007), and preferentially, the molar percentage of the three substances relative to the halogenated aryl hydrocarbon or the aryl alkyne is 0.03/0.6/0.6. The method can also perform catalytic reaction by using a mother liquor of the filtered product and other solid matters of the coupling reaction to prepare the diaryl acetylene monomer liquid crystal continuously. The method provides a novel catalytic reaction system for synthesizing a diaryl phenylacetylene monomer liquid crystal, the catalyst is cheap and easy to obtain and can be used repeatedly, the separation and purification processes of the liquid crystal product are simple, the products after the reaction are directly filtered out, and the obtained monomer liquid crystal has stable quality and high yield and can greatly reduce the production cost and reduce the waste emission.