Objective: Screening of polyvinyl alcohol-fish gelatin-solanum nigrum anthocyanin （PVA/FG-SNA） composite packaging film with optimal structure and properties. Methods: Optimizing the fabrication process of films through orthogonal tests, and using thickness, moisture content, water vapor permeability （WVP）, tensile strength （TS）, elongation at break （EB）, Fourier infrared spectroscopy （FTIR）, X-diffraction （XRD）, scanning electron microscopy （SEM）, and thermogravimetric （TG） analysis to explore the effects of SNAs with different mass fractions on the properties and microstructures of PVA-FG film; In addition, the pH color response and NH₃ sensitivity of the PVA/FG-SNA composite film were monitored. Results: When the mass ratio of PVA-to-FG, heating temperature and time were 60∶40, 95 ℃, and 1.5 h, respectively. The water solubility and WVP of the PVA-FG film were （36.03±2.63）%, and 2.91×10^-4 g·mm/（m²·h·Pa）, separately. With the increment of SNA dosage, the thickness, moisture content, WVP, and EB of the PVA-FG film also increased. When the mass fraction of SNA was 0.2%, the thickness, moisture content, WVP, TS, and EB of the composite film were （0.07±0.01） mm, （11.09±0.25）%, 5.45×10^-4 g·mm/（m²·h·Pa）, （21.12±1.07） MPa, and （373.77±8.59）%, respectively. At the same time the composite film had good compatibility among its components. In addition, the PVA/FG-0.2% SNA film showed good color response under NH₃ atmosphere conditions, which could be used as a pH-indicating film. Conclusion: This article optimized the water resistance of the PVA-FG composite base film. The hydrophobic and mechanical properties of the PVA-FG composite base film are negatively correlated with the amount of SNA dosage, and SNA can significantly enhance the pH and NH₃ sensitivity of the film.