A series of para-substituted 1,3-diphenyl-1,3-propanedione compounds have been synthesized by the Claisen condensation reaction of different substituted aromatic ketone and ester. Experiment based upon orthogonal design with four factors and three levels was carried out for optimization of conditions for 1,3-bis-(4-Methoxy-phenyl)-1,3-propanedione. Experimental results showed the suitable conditions as follows：using toluene as solvent and sodium amide as catalyst, n(p-methoxy acetophenone):n (methyl-p-methoxybenzoate):n (sodium amide ) = 1:4:5. microwave irradiation power was 320W and reaction time 45min. The yield can achieve 72.1%.The structures of synthetic products were characterized by IR and 1HNMR .HPLC was selected to determine the concentration of products. The products are good UV ultraviolet absorbents and exhibit significant antioxidation activity on lard..