Mixed polymer brush-grafted particles, in which two distinct polymers are randomly or alternately immobilized by one end via a covalent bond oil the surface of core particles with sufficiently high grafting densities, represent a new, intriguing class of environmentally responsive nanostructured hybrid materials. The two end-tethered polymers can undergo spontaneous chain reorganization in response to environmental variations, rendering particles adaptive surface properties and different colloidal behavior. This Perspective is intended to review recent exciting progress oil the synthesis, responsive properties, self-assembled structures, and applications of mixed brush-grafted particles with a spherical core radius R-core significantly larger than, comparable to,a rid smaller than the root-mean-square end-to-end distances (< R-rms >) of grafted polymers. The critical yet unsolved issues in the phase morphology of mixed homopolymer brushes and the hierarchical self-assembly of mixed brush-grafted particles are discussed.