Density functional theory was applied to investigate the cooperative aggregation of comblike copolymer and linear homopolymer blends in selective solvents, where the linear homopolymers are set to be identical to the hydrophobic side chains of the comblike copolymers. The effects of the composition and the length of the linear homopolymers, as well as solvent quality, on the cooperative aggregation were studied systematically. The results show that large aggregates of macrophase separation can always be formed with the addition of linear homopolymers, where the homopolymers accumulate at the center and the comblike copolymers as the corona with the hydrophobic blocks distribute at the core/corona interface. This work demonstrates that the structure and size of micelles can be tuned by the controlled addition of appropriate linear homopolymers, leading to a better understanding of the controlled synthesis of micelles with target structure and properties.