A polyester resin which includes acid components having aromatic dibasic acid component and trivalent or higher acid component; alcohol components including aliphatic, aromatic or cycloaliphatic diol component, and trihydric or higher alcohol component; polyolefin polyol having 1,800 to 2,500 number average molecular weight and hydroxyl value of 40 to 55 KOHmg/g; and wax having melting point of 80 to 110, wherein the amount of the polyolefin polyol is 0.1 to 2 weight % and the amount of the wax is 0.5 to 15 weight % with respect to the total polyester resin. Also disclosed is a method for preparing polyester resin by (a) carrying out an esterification reaction or an ester exchange reaction with the acid components, the alcohol components, and the polyolefin polyol; and (b) carrying out a polycondensation reaction for reaction product of the esterification or ester exchange reaction in the presence of the wax.