In this study, the color variation of spun-dyed polyester filaments was systematically investigated using various processing technology parameters including linear density, velocity of cross-flow air, different processing ways and different textured technology parameters. The results showed that these parameters had varying degrees of influence on the color of spun-dyed polyester filament in processing. The degrees of color variation were expressed using the CIE1976 L*a*b* system. As a result, it provided an important theoretical guidance for working out actual production technology and controlling color quality of spun- dyed polyester filaments based on actual industrial equipment and technological conditions.