Abstract: The microwave-assisted racemization technology of L-phenylalanine was studied in this paper. Microwave irradiation or conventional heating method,power,catalysts solvents and other factors of reaction were investigated in racemization of L phenylalanine,and the racemic regularity of L-phenylalanine is explored by racemization theory. The results showed Racemization reaction of L-phenylalanine with microwave irradiation （300 W） was carried out in the presence of salicylic aldehyde in acetic acid. Racemic phenylalanine was obtained with specific rotation of-1.27° and yield of 81.4 % for 4 h,and effectiveness of racemization was superior to that of other reaction condition. It was feasible that microwave-racemization reaction of L-phenylalanine was performed in the presence of salicylic aldehyde in acetic acid.