The work aims to prepare nano-silver sol by microwave heating with pumpkin cooking liquid and AgNO3 as raw materials and APG as surfactant to study its preparation process, performance and antibacterial effect. The preparation of AgNPs was optimized by single factor. UV-vis, TEM, EDS, and XRD were used to analyze the characteristic absorption peaks, morphology, structure and stability of the synthesized silver nanoparticles. The antibacterial properties of AgNPs against E.coli and S.aureus were determined. The optimum technological conditions for preparation of AgNPs were as follows:in 40 mL of pumpkin cooking liquid, AgNO3 initial concentration 1.2 g/L, pH value 13, microwave heating time 60 s. After optimization, the UV-vis spectra of the prepared AgNPs showed strong characteristic absorption peaks at 406 nm, and the EDS spectrum further confirmed the existence of AgNPs. AgNPs were spherical with an average particle size of 13.4 nm, small particle size and good dispersion and stability. The antibacterial test showed that AgNPs of different concentrations had strong inhibition and killing effect on E.coli and S.aureus. The MIC and MBC of E.coli were 5 mg/L and 10 mg/L, respectively, and the MIC and MBC of S.aureus were 40 mg/L and 320 mg/L, respectively. The AgNPs has antibacterial ability against G- and G+ bacteria and has good application prospects in food packaging.