Diethyl malonate is an important intermediate for the preparation of 2-amino-4, 6-dimethoxy-pyrimidine, which can be used for the preparation of sulfonylurea herbicides, such as benzsulfuron, pyrisulfuron, nicosulfuron, etc., and is also an intermediate for sulfonamide drugs and barbiturates in medicine. It can also be used for gas chromatography fixed liquid (maximum use temperature 40℃, the solvent is benzene, chloroform, ethanol) to detect ammonia and potassium. In addition, diethyl malonate is also GB2760-96 provisions for the permitted use of edible spices, mainly used in the preparation of pear, apple, grape, cherry and other fruit flavor.