The method of extracting natural preservative in rosemary and its bacteriostasis were studied.The results showed: The optimal technical parameters of extracting natural preservatives from rosemary by edible alcohol were ratio of solid to liquid of 1:15,temperature of extraction of 80℃ and time of extraction of 15h;The alcohol extraction of rosemary had strong inhibition effect on common food-contaminating microbes.The MIC was 6.25mg·mL-1 for Staphlococcus aureus and Bacillus subtilis and 12.5mg·mL-1 for Esc...