Abstract: Cellulose nanocrystals (CNC) are nanomaterials with excellent mechanical properties, optical properties and surface chemical properties, which have attracted wide attention from researchers in recent years. CNC-based sensors have a single, double and multiple response to external environmental stimuli, such as humidity, gas, pH, solvent, temperature, light and other drive sensing, which makes it in the information encryption, health detection, food, environmental monitoring, energy storage, wearable and other fields show great application potential. In this paper, the key characteristics of CNC are briefly introduced, and the important application development and research mechanism of multi-functional sensors based on CNC are analyzed. Finally, the main problems and challenges in the preparation process of CNC-based sensor materials are summarized, and the reference is provided for improving their performance and functional innovative applications.