In this work, the effect of purple sugarcane (Saccharum officinarum) peel anthocyanin extracts (PSPAEs) on the physical and functional properties of films based on lemon peel waste pectin (LPP) was investigated for the first time. PSPAEs have great compatibility with LPP matrix, and the LPP/PSPAEs composite film demonstrated a higher ultraviolet light barrier capacity. The incorporation of PSPAEs significantly improved the physical properties of LPP films confirmed by the enhanced mechanical properties and thermal stability, which might be associated with the more compact structure observed by scanning electron microscope images and possible intermolecular interaction such as hydrogen bond interactions between film components demonstrated via Fourier transform infrared spectra and X-ray diffraction analysis. Furthermore, PSPAEs imparted excellent functional properties on LPP films, including antioxidant properties and sensitive color response to the pH alternation and ammonia atmosphere, which favored the possible application in monitoring food freshness. Herein, LPP/PSPAEs films were employed to detect the freshness of shrimp and beef, and a visually discernible color change could be observed as the food turned from fresh to stale. In addition, the LPP/PSPAEs composite films displayed great biodegradability in the soil. The results showed that could impart excellent properties on LPP films, and LPP/PSPAEs composite film is a promising biodegradable film that can be used for intelligent detection of food freshness. Display omitted •Films based on lemon peel waste pectin (LPP) were prepared.•Purple sugarcane peel anthocyanin extracts (PSPAEs) were added into LPP films.•20–30% PSPAEs improved mechanical properties and thermal stability of LPP films.•PSPAEs effectively imparted excellent functional properties on LPP films.•LPP/30% PSPAEs composite films showed promise for the detection of food freshness.