The active substance was extracted from seven kinds of spices: nutmeg, cinnamon, thyme, Helichrysum italicum, Hypericum perforatum, licorice and rosemary, by use of ethanol. Then determined the minimal inhibitory concentration (MIC) of different extracts against 4 pathogenic bacteria: Escherichia coli, Staphyloccocus aureus, Vibrio parahaemolyticu and Salmonella typhimurium. The result suggests that, the MIC of nutmeg extraction was above 0.5% (V/V). The MIC of cinnamon extraction against Escherichia coli, Staphyloccocus aureus were both 0.2% (V/V), and the other MIC of different extraction were all 0.5% (V/V). According to the MIC results, this experiment chosen the other six kinds of spices except nutmeg as the raw material to prepare a kind of natural herbal bacteriostatic agent, and the antibacterial performance was evaluated. The experimental results indicated that, this natural herbal bacteriostatic agent had significant bactericidal effect against six experimental bacteria and the sterilization rate reached 99.99%. In strawberries preservation, this natural herbal bacteriostatic agent showed a better effect, and extending shelf life from 7 days to 10 days.