NOVELTY - Biphenyl and chloroacetyl chloride are reacted with solvent in presence of aluminum tricholride catalyst to carry out Friedel-Crafts acylation to obtain 4-phenyl-( alpha )-chloro-acetophenone. The 4-phenyl-( alpha )-chloro-acetophenone and neopentyl glycol are subjected to condensation reaction in presence of p-toluenesulfonic acid catalyst to obtain solution, which is neutralized and recrystallized to obtain intermediate ketal, which is subjected to rearrangement reaction to obtain crude 4-biphenylacetic acid, which is recrystallized to obtain 4-biphenylacetic acid.    USE - Preparation of 4-biphenylacetic acid used for pharmaceutical.    ADVANTAGE - The method economically provides 4-biphenylacetic acid without generating toxicity.    DETAILED DESCRIPTION - Biphenyl and chloroacetyl chloride are reacted with solvent chosen from chloroform, dichloromethane or 1,2-dichloroethane, in presence of aluminum trichloride catalyst at -20 to 30 degrees C to carry out Friedel-Crafts acylation to obtain 4-phenyl-( alpha )-chloro-acetophenone. The 4-phenyl-( alpha )-chloro-acetophenone and neopentyl glycol are subjected to condensation reaction using solvent chosen from toluene and/or n-heptane in presence of cresyl phosphate catalyst to obtain solution. The obtained solution is neutralized by inorganic alkali, washed with hot water, and the unreacted p-toluenesulfonic acid and neopentyl glycol are removed. The obtained solution is recrystallized with petroleum ether, methyl alcohol or ethyl alcohol to obtain intermediate ketal having purity of 95% or more. The intermediate ketal is subjected to hydrolytic acidification by rearrangement reaction using solvent of methyl alcohol, ethylalcohol or petroleum ether, in presence of zinc chloride, or mixture of zinc oxide and zinc as catalyst to obtain crude 4-biphenyl acetate. The obtained 4-biphenyl acetate is hydrolyzed with alkali, impurities are removed and bleached to obtain crude 4-biphenylacetic acid. The crude 4-biphenylacetic acid is recrystallized by alcohol, ethyl acetate, or 40-70% of acetic acid to obtain 4-biphenyl acetic acid having purity of 99.8%. The molar ratio of biphenyl, aluminum trichloride and chloroacetyl chloride is 1:1-1.5:1-1.5. The molar ratio of 4-phenyl-( alpha )-chloro-acetophenone, neopentyl glycol and p-toluenesulfonic acid is 1:1-1.2:0.1-0.3.