The aim of this study was to analyse the effect of nanocomposite packaging material (Nano-PM) on the physicochemical characteristics and antioxidant capacity of mushrooms (Flammulina velutipes) during 21 days of postharvest storage at 4 °C. The results showed that Nano-PM improved retention of nutrients and inhibited the weight loss, respiration and distinct stipe elongation of mushrooms compared with the Normal packing material (Normal-PM). Reactive oxygen species (ROS) levels, including superoxide radical (O2−) and hydrogen peroxide (H2O2), increased during storage. Membrane damage, as measured by relative electrolyte leakage and malondi-aldehyde (MDA) contents also increased. However, levels of O2− and H2O2, relative electrolyte leakage and MDA contents were all significantly lower (P