The invention relates to low-color-difference 
polyester wool-like different-shrinkage complex 
yarn and a preparation method thereof. The low-color-difference 
polyester wool-like different-shrinkage complex 
yarn is prepared through carrying out 
fiber intermingling on low-color-difference 
polyester POY (Pre-Oriented 
Yarn) and low-color-difference polyester FDY (Fully Drawn 
Yarn), wherein the low-color-difference polyester POY forms small 
yarn loops which surround the low-color-difference polyester FDY; the low-color-difference polyester POY and the low-color-difference polyester FDY are made from polyester through carrying out dissolving and washing and then carrying out 
spinning. The low-color-difference polyester 
wool-like different-shrinkage complex yarn has the rupture strength not lower than 3.0cN / dtex, the breaking elongation of 40.0+ / -3.0%, the 
crimp contraction of 5.50+ / -3.0%, the interlacing degree of 95+ / -5 / m, the 
fiber number of 150dtex to 300dtex and the 
color difference [
delta]E smaller than 0.200. According to the low-color-difference polyester wool-like different-shrinkage complex yarn and the preparation method thereof, 
ethylene glycol 
magnesium is relatively mild and has a very small thermal degradation coefficient, and the oligomers are reduced during 
polymerization and are further reduced during washing, so that during the 
dyeing and postprocessing thermosetting of polyester fibers, the amount of the oligomers migrating to the outside of the fibers from the inside is reduced, the occurrence of color spots and streaks is reduced, and the level dyeability and 
rubbing fastness of the fibers are guaranteed.