Abstract: Nanocellulose is an abundant, eco-friendly, and renewable resource, as a cellulose-derived material, it is characterized by high mechanical strength, high crystallinity, and large specific surface area due to its special structural properties. Nanocellulose-based humidity-responsive smart devices show excellent sensitivity and fast response due to its abundant hydrophilic groups (such as hydroxyl and carboxyl groups). Nanocellulose can be used as a humidity sensitive material to prepare high-performance humidity-responsive smart devices. This paper provides a concise overview of nanocellulose, its classification, and sources, along with an exploration of the classification and response principle of humidity responsive smart devices. The primary focuses lie in the application of nanocellulose within the context of humidity-responsive smart devices, and summarized the performance, advantages and disadvantages of different types of humidity responsive smart devices composited with nanocellulose and conductive materials. Finally, this paper conclude the problems and challenges in the potential research applications of nanocellulose-based humidity-responsive smart devices, aiming to offer theoretical support for the advancement of nanocellulose-based composites in humidity-responsive smart devices.