The present invention provides a terephthalic acid ester composition comprising at least three different terephthalic acid compounds. In this composition, at least one of those three different compounds has the terephthalic add with a different substituent and at least two of those compounds have the terephthalic acid with an identical substituent, the molar ratio of the compound having the terephthalic add with an identical substituent is 6-80 mol% for the total mol of the composition, and the molar ratio of the compound having the terephthalic add with a different substituent is 20-94 mol%.The composition of the present invention increases physical properties of polymer resin molded product including tensile strength, heating loss, elongation, age resistance and weatherability when it is added as a plastidzer during the processing of polyvinylchloride resin.