L-phenylalanine is a bioactive aromatic amino acid. It is a necessary amino acid which cannot be self-synthesized by human and animals. It is necessary for a person to intake 2.2g L-phenylalanine every day. As one of the eight necessary amino acids for human body, it has been widely used in pharmaceutical and food additive industry. It is an important ingredient of amino acid injection. In food processing industry, L-phenylalanine can be added into bakery foods. And the nutrition of phenylalanine can be enhanced and by amido-carboxylation with glucide. L-phenylalanine can enhance foods aroma and keep the balance of necessary amino acids. In pharmaceutical industry, L-phenylalanine is used as intermediate of some amino anticancer pharmaceuticals such as formylmerphalanum and etc. It is also used to manufacture adrenalin, thyroxin and melanin. Another important application is to synthesize aspartame with L-aspartic acid.