The work aims to prepare degradable composite membranes with antioxidant and antibacterial properties by using PSPA-AgNPs as antimicrobial agent and investigate their preservation effects on cherry tomatoes. PSPA-AgNPs was prepared by hydrothermal method and then added into chitosan quaternary ammonium salt and other matrices as antimicrobial agent to prepare fully bio-based degradable composite membranes. The effects of PSPA-AgNPs on the composite membranes were investigated through the determination of mechanical properties, barrier properties, optical properties, antioxidant and antimicrobial properties of the composite membranes. The preservation effects of the composite membranes were examined by taking the weight loss rate, hardness, total soluble solids content, titratable acid content and vitamin C content of the cherry tomatoes as the indexes. The barrier property and antioxidant and antimicrobial properties of the composite membranes were significantly improved with the addition of PSPA-AgNPs. Among them, the barrier property of the composite membranes was the best when the content of PSPA-AgNPs was 10%. The bacterial inhibition rate of the composite membranes reached 99% when the content of PSPA-AgNPs reached 30%, increasing by a factor of 1. The antioxidant activeness increased from 29.87% to 50.27%, which was improved by 68.30%. In addition, the preservation effect of Q/S/H-AgNPs composite membrane was comparable to that of PE preservation membrane, which could effectively slow down the rate of decline in the quality, hardness, and nutrient content of cherry tomatoes. Therefore, the Q/S/H-AgNPs composite membrane effectively improves the storage quality and prolongs the shelf life of the cherry tomatoes, and possesses the potential for the preparation of fully bio-based biodegradable active packaging materials.