In order to prepare 2,6-dimethyl-4-phenylpyridine-3,5-dicarboxylic acid, firstly, by Hantzsch reaction, diethyl 1,4-dihydro-2,6-dimethyl-4-phenylpyridine-3,5-dicarboxylate was prepared by 0.10 mol benzaldehyde, 0.25 mol ethyl acetoacetate and 0.125 mol ammonium bicarbonate, refluxing 0.5 h in the solvent of 40 mL methanol. Under the condition of stirring, the yield was 45.9%. Secondly,  0.01 mol diethyl 1,4-dihydro-2,6- dimethyl-4-phenylpyridine-3,5-dicarboxylate and 0.02 mmol ferric chloride hexahydrate was added to the reaction system to form the corresponding aromatization diethyl 2,6-dimethyl-4-phenylpyridine- 3,5-dicarboxylate under refluxing condition, the yield was 50.2%. Finally the product was synthesized by hydrolyzation, the yield was 62.7%.