Current development in cellulose-based sensors remain restricted by limited mechanical strength and insufficient sensitivity range. Inspired by coral structure, we report a Janus cellulose aerogel (JCA) based triboelectric sensor (JCAS) featuring a unique double cellulose crosslinked network. The biomimetic structure enhances intermolecular interactions and optimizes the molecular chain structure, significantly improving mechanical stability and operational durability. Consequently, the JCA demonstrates a remarkable 437.5% increase in Young's modulus compared to pristine cellulose aerogel (PCA), enabling it to withstand loads over 50 000 times its own weight. The corresponding JCAS exhibits high performance, including stable operation under high-pressure (300 kPa for 4 h), an extended cycling longevity, and a reliable sensing range of 0–800 kPa which is the widest reported to date for cellulose-based triboelectric sensors to our knowledge. Biocompatibility tests further confirm their suitability for wearable applications. Finally, we demonstrate the practical utility of JCASs by integrating them into wearable devices for human posture recognition. This work provides a novel strategy for synthesizing crosslinked cellulose aerogels, promoting the practical applications of cellulose-based triboelectric sensors.