The scope of this study was to investigate the effect of the blend ratio on the structure and properties of dual-feed-opening rotor-spun yarn. A variety of yarns with different blended ratios were spun from two viscose fibers with the same properties but different colors. Through digital image processing technology, the ratios of the area occupied by the two fibers on the surface and the cross-section of the yarns were obtained. The results showed that the yarns with blend ratios of 40/60 and 50/50 had an obvious spacing phenomenon of two fiber segments on the surface. The ratio of the area occupied by the two fibers on the yarn surface was not equal to the value of the blend ratio. In the yarn cross-section, the difference in the area ratio of the two fibers to the blend ratio was subtle. The blend ratio had little effect on the mechanical properties (strength and elongation at break). However, the quantities of hairiness fluctuated greatly. The mass irregularity and imperfections decreased as the blend ratio approached 50/50. This work provides important guiding insights for the research of dual-feed-opening rotor-blended yarn.