NOVELTY - A polyethylene terephthalate composition comprises 1-3 mol/ton alkali metal phosphate compound as alkali metal element content, 1.5-5 mol/ton phosphorus element, 1 ppm by volume or less white foreign material containing phosphorus element and alkali metal element and having size of 50 mu m or more, and 15 eq/ton or less carboxylic acid terminal group having increased amount of the carboxylic acid terminal group (( delta )COOH) of 30 eq/ton or less when the composition is subjected to a wet heat treatment at 155 degrees C under 100% RH atmosphere, for 4 hours.    USE - Polyethylene terephthalate composition is used for electric material, magnetic material, capacitor, packaging, optical applications and film for solar cell front sheet.    ADVANTAGE - The polyethylene terephthalate composition has excellent long-term hydrolysis resistance and optical characteristics, and low oligomer property.    DETAILED DESCRIPTION - A polyethylene terephthalate composition comprises 1-3 mol/ton alkali metal phosphate compound as alkali metal element content, 1.5-5 mol/ton phosphorus element, 1 ppm by volume or less white foreign material containing phosphorus element and alkali metal element and having size of 50 mu m or more, and 15 eq/ton or less carboxylic acid terminal group having increased amount of the carboxylic acid terminal group (( delta )COOH) of 30 eq/ton or less when the composition is subjected to a wet heat treatment at 155 degrees C under 100% RH atmosphere, for 4 hours. The white foreign material has inherent viscosity of 0.65-0.9 dl/g, and comprises 0.6 wt.% or less cyclic trimer. An INDEPENDENT CLAIM is included for manufacture of polyethylene terephthalate resin composition, which involves supplying terephthalic acid and ethylene glycol to ethylene terephthalate low polymer, performing polycondensation reaction and solid state polymerization through esterification, and adding alkali metal phosphate compound by the time of starting polycondensation reaction.