Cellulose-based hydrogels (CBHs) have shown important application value in the field of flexible sensing due to their excellent biocompatibility, degradability and controllability. This chapter focuses on the conductive properties, environmental stability and its application in wearable devices. By compositing conductive materials (such as MXene, conductive polymers), CBHs can achieve conductivity of 1–5 S/m and have sensor characteristics of fast response (response time <200 ms) and wide strain range (0–1000%). Their unique dual network structure design balances mechanical strength and conductivity, while endowing the material with self-healing, antifreeze (maintaining flexibility at −40 °C), and antibacterial properties to support long-term use in wearable devices. In terms of application, CBHs have been successfully used to monitor human movement (such as joint bending, pulse) and environmental parameters (such as temperature, sweat components). Most of cellulose raw materials are derived from agricultural waste, reflecting the concept of green and sustainable development. In the future, CBHs have broad prospects in fields such as smart medical care and human–computer interaction.