A low chromatic aberration polyester different-shrinkage composite yarn is made of polyester POY yarn and polyester FDY composite yarn. The polyester POY yarn and polyester FDY yarn is obtained by spinning the polyester solution, the rupture strength of the low color polyester different-shrinkage composite yarn is ≥1.9 cN/dtex, the elongation at break is 30.0±5.0%, the crimp shrinkage is 2.50±3.0%, the network degree is 20±5/m, the color difference ΔE is less than 0.200. In the invention, the magnesium ethylene glycol is relatively mild, the thermal degradation coefficient is small, the oligomers in the polymerization process is reduced, and the oligomers in the dissolution process are further reduced, so that the appearance of stains and streaks reduces during the dyeing and post-processing heat setting of the polyester fiber, which ensures the fiber's leveling and rubbing fastness.