The present invention relates to a method of manufacturing a diester-based compound, and, more particularly, to a method of manufacturing a diester-based compound, which is performed using a continuous process including a reaction part in which a total of n reaction units spanning from a first reaction unit to an nth reaction unit are connected in series, wherein each of the reaction units includes a reactor, and the method includes: supplying a feed stream including a dicarboxylic acid and an alcohol into the first reactor; esterifying the feed stream to prepare a reaction product; and supplying a lower discharge stream including the reaction product into the reactor of the rear reaction unit. In this case, a conversion rate of the esterification reaction in the first reactor is controlled in a range of 50 to 80%.

Provided is a method of preparing a diester-based material, more particularly, a method of preparing a diester-based material, which is carried out by a continuous preparation process of a diester-based material including a reaction part in which a total of n reaction units from a first reaction unit to an nth reaction unit are connected in series, the reaction unit including a reactor which esterifies dicarboxylic acid and alcohol, including: esterifying dicarboxylic acid and alcohol in a reactor of the first reaction unit to produce a reaction product, and supplying a lower discharge stream including the reaction product to a reaction unit at a rear end through a lower discharge line; and supplying a liquid material through a liquid supply line connected to a lower discharge line of the reactor of the first reaction unit.