A novel intelligent film was developed by immobilizing 1%, 3% and 5% black rice bran anthocyanins (BACNs) into oxidized-chitin nanocrystals (O-ChNCs)/ chitosan (CS) matrix. The ultraviolet-visible spectrum of BACNs solutions showed color variations from red to greyish green in a range of pH 2.0–12.0. Fourier transform infrared spectrum and atomic force microscope of the films showed that O-ChNC and BACNs were well dispersed into the CS matrix. Although the incorporation of BACNs decreased the mechanical and barrier properties of the CS/O-ChNCs/BACNs (COB) films, it endowed the COB films with excellent UV-barrier, antioxidant and pH sensitivity character. The results of the application trial showed that the COB films containing 3% of BACNs (COB-3) were able to monitor the spoiling of fish and shrimp by visible color changes. Therefore, the developed COB-3 films could be used as an intelligent food packaging for monitoring animal-based protein food spoilage.