Abstract: In this paper, the optimum extractive technology of bacteriostasis from chestnut shells and its antibacterial activity were studied by using single factor experiment and orthogonal experiment, and then the bacteriostatic activity of chestnut shell extracts and the effects of temperature, pH value on it were studied by cylinder plate method. The results showed that optimum extractive technology of bacteriostasis from chestnut shells were as follows: ethyl acetate as solvent, extracting time 4.0 h, extracting temperature 70℃, and ratio of solid to liquid 1：30. The substance extracted showed some antibiotic activity against Escherichia coli, Staphylococcus aureus, Bacillus subtilis and the minimum inhibitory concentrations (MIC) were 0.125, 0.0625, 0.125 mg/mL, respectively, and the minimum bactericidal concentrations (MBC) were 0.125, 0.125, 0.25 mg/mL respectively. It could meet the moment heat treatment and had strong antimicrobial activity within pH 7-9.