Nanocellulose, as a sustainable biodegradable nanomaterial, was added to conductive hydrogels to improve their properties. The applications of nanocellulose in different conductive hydrogels were discussed in this paper. The advantages of nanocellulose-based conductive hydrogel and its applications in flexible sensor were introduced in details. Finally, the challenges and future development directions of nanocellulose-based conductive hydrogels applied in flexible sensors were discussed.