Cellulose nanocrystal (CNC) plays a more and more important role in the process of designing and assembly of functional materials, due to its high strength and modulus, controllable structure, feasible modification, biocompatibility and biodegradability. As a kind of macromolecule system with "intelligent" behavior, the stimuli-responsively functional materials make a sensitive response when stimulated by the external environment, and show the corresponding function. With the addition of CNCs,

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... ot only the mechanical properties of CNC-based functional materials are greatly improved, but also the hydroxyl and carboxyl groups on the surface of CNCs provide a convenient way to enrich the stimulus response source of these functional materials. Herein, combining with the chemical structure of CNC, the synthesis of CNC-based stimuli-responsive functional materials was comprehensively summarized. Meanwhile, the recent developments of single or multiple stimuli-responsive functional materials based on CNCs, such as water-, thermal-, pH-, light-responsive functional materials were summarized, with the stimulate switch taken as the main line. Finally, it was pointed out that future research would focus on improving the surface-modification efficiency of CNC, and broadening multi-stimulus responsiveness of CNC-based functional materials. The preparation of CNC-based functional materials with high performances will be significant in the future research as well.