The carbonylation of alpha-Bromo-p-xylene (BrCH2C6H4CH3, BX) with iron pentacarbonyl (Fe(CO)(5)) by phase-transfer catalysis was studied in an organic solvent/alkaline solution. The reaction mechanism was corrected and clarified. The concentrations of base, reactant and catalyst, volume ratio, the kind of catalysts, organometals and solvents were evaluated to find the optimum condition in this reaction. The technique of phase-transfer catalysis has a dramatic accelerating effect on the reaction. In examining eight kinds of phase-transfer catalysts, tetra-n-butylammonium cation and tetra-n-butylphosphonium cation were found to be the best for increasing the yield of bis(p-methylbenzyl) ketone ((p-CH3C6H4CH2)(2)CO, BMBK). The amount of phase-transfer catalyst, the concentration of NaOH, the molar ratio of EX to Fe(CO)(5) and the volume ratio of aqueous to organic phase affected the product selectivity.