Provided is a method for manufacturing a terephthalate-based composition, the method comprising: a step (S1) of flowing in a dialkyl terephthalate in which alkyl has 7 to 10 carbon atoms and a primary alcohol with a low boiling point having 4 or 5 carbon atoms into a reactor and performing transesterification of the dialkyl terephthalate and the primary alcohol with a low boiling point; and a step (S2) of extracting in a reduced pressure an unreacted material and a by-product from the reactor after finishing the transesterification, wherein the step S1 comprises a pressure-applying step in which the pressure of the reactor is 1.5 to 2.5 bar.