The invention discloses a side fluorine-containing type biphenyl diluent for high-birefringence liquid crystal and a synthesis method thereof. A structural formula of the side fluorine-containing typebiphenyl diluent is as shown in the description, wherein in the structural formula, X1 and X2 represent H or F, one and only one of X1 and X2 is F, R represents C1 to C4 alkyl groups, synthesis is carried out by adopting Suzuki coupling and Witting reactions which are industrially matured, and the synthesis method is simple and efficient. According to the side fluorine-containing type biphenyl diluent disclosed by the invention, the structure contains side fluorine substituent groups and butylene substituent groups, so that the low-temperature performance of the high-birefringence liquid crystal can be effectively improved, and the viscosity of the side fluorine-containing type biphenyl diluent is lower than a commercial diluent 3HHV, the birefringence is 6 to 6.5 times higher than that of the commercial diluent 3HHV, and the high birefringence (which is greater than 0.25) of a liquid crystal material can be ensured while the rotary viscosity of the high-birefringence liquid crystal is reduced.