Indicating current manufacturing shortcomings for D-dihydrophenylglycine and propose improvement program, the paper adjusted the ratio of raw materials and the reaction products purified and crystallized way to change the target to achieve a substantial reduction reaction byproducts 4,5-dihydrocyclohexylglycine purposes. Improved synthesis of D(-)-2,5-dihydrophenylglycine has yield 92% or more, and 4,5-dihydrocyclohexylglycine 1.2% or less.