A method for preparing a low migration plasticizer of di-2-ethylhexyl phthalate is provided. The method includes a step of adding at least one short chain alcohol component and at least one long chain alcohol component in an esterification reaction between terephthalic acid and 2-ethylhexanol, so as to graft modify a resulting di-2-ethylhexyl phthalate. The esterification reaction is carried out under a temperature from 30° C. to 225° C. and a pressure from 80 mbar to 1033 mbar.