Metabolism, transpiration, and invasion of pathogens during the storage and transportation of fruits can lead to significant waste and even food safety issues. Therefore, real-time, rapid, and accurate non-destructive monitoring of physiological information during the storage of fruits and vegetables to assess fruit freshness is crucial. Herein, we engineered a degradable and multifunctional humidity sensing film for monitoring fruit freshness. The film is fabricated through the co-assembly of bagasse cellulose nanocrystals (CNC), okra polysaccharides (OPs), silver nanowires (Ag NWs), and phytic acid (PA), utilizing dynamic hydrogen and phosphate bonds. This innovative design endows the CNC/OPs/PA/Ag NWs (COPA) composite film with outstanding mechanical properties, water resistance, low water vapor permeability, antibacterial, degradability, and moisture-sensing ability. Notably, the proposed COPA humidity sensor exhibits high linearity (R² = 0.994), ultralow hysteresis (1.24%), and 32 days of operational stability across a 35%–98% relative humidity (RH) range, enabling precise freshness monitoring during fruit storage. Significantly, the COPA film prolonged the shelf-life of packaged fruit when compared to conventional PE film packaging. This research establishes a foundational framework for next-generation smart sensors in food quality management and biomedical monitoring applications.