The invention relates to alkyl/alkenyl-modified difunctional biphenyl compounds and a preparation method thereof. The preparation method comprises the following step: by controlling the reaction temperature at 50-110 DEG C in an organic solvent, carrying out reaction on 2-iodobiphenyl, chloralkane and olefin by using the Pd element as a catalyst for 2-24 hours in the presence of an alkali, a reducer and additives, thereby obtaining the alkyl/alkenyl-modified difunctional biphenyl compounds. Compared with the prior art, the synthesis method of the alkyl/alkenyl-modified difunctional biphenyl compounds is completed for the first time. The method has the advantages of mild conditions, high yield, wide substrate application range and the like, and is simple to operate.