The invention relates to a super-bright 
polyester partially oriented 
yarn and a preparation method thereof. The preparation method comprises the following steps: uniformly mixing 
terephthalic acid, 
ethylene glycol, dihydric 
alcohol containing 
silicon on a main chain, a 
fluorine-containing 
binary acid, 2,2,3,4,5,5-hexamethyl-3,4-hexanediol and doped modified ZrO2 
powder, sequentially carrying out an 
esterification reaction and a condensation 
polymerization reaction so as to prepare modified 
polyester; and preparing modified 
polyester POY yarns from the modified polyester melt according to a POYprocess by adopting a triangular spinneret plate, thereby obtaining the super-bright polyester partially oriented 
yarn. The prepared super-bright polyester partially oriented 
yarn is high in dye-uptake, K / S value and color fastness during 
dyeing, and the national degradation speed is high. According to the addition of the 2,2,3,4,5,5-hexamethyl-3,4-hexanediol and the dihydric 
alcohol containing 
silicon on the main chain, the 
dyeing property of fibers is improved, and due to the addition of the 
fluorine-containing 
binary acid and the doped modified ZrO2 
powder, the degradation performance of the polyester is improved; and the prepared product is excellent in 
dyeing property and degradation property.