The invention relates to a synthesis method of 1-(4-chlorphenyl)-2-cyclopropyl-1-acetone. The method consists of: subjecting 4-chlorophenylacetonitrile, cyclopropyl methyl ketone, strong alkali and a phase transfer catalyst to reaction in a solvent, then in the presence of a catalyst and in a solvent, performing reduction with magnesium powder, and finally introducing oxygen or air into the product and alkali in the presence of the phase transfer catalyst to conduct oxidation treatment, thus obtaining 1-(4-chlorphenyl)-2-cyclopropyl-1-acetone. Compared with the prior art, by introducing the catalyst, the method lowers the reaction temperature, eliminates tar, increases the yield and purity, reduces the cost, and also reduces generation of impurities, has small environmental pressure, and occupies little equipment. The preparation method has the advantages of simple process, simple operation, mild condition and high yield, and is suitable for large-scale industrial production.