Abstract: In order to study the inhibitory effect of 10 kinds of Chinese herbal medicine including honeysuckle， folium isatidis against avian E. coli in vitro， an external bacteriostasis experiment was conducted for the 10 kinds of Chinese herbal medicine by using concurrently the KirbyBauer method and punch method， then a better method for inhibitory test was selected， and the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of the highly sensitive Chinese herbal medicine against avian E. coli was determined. The results showed that bacteriostasis circle size of two methods showed significant differences (P≤005) except for the licorice， heavy flooror， and showed extremely significant differences (P＜001)for honeysuckle， cortex phellodendri， cyrtomium rhizome， rhizoma coptidis among them，which indicated that the KirbyBauer method was better. The bacteriostasis diameter of honeysuckle and coptis were larger among the10 kinds of Chinese herbal medicine， which were (1510±001) mm， (1602±001) mm respectively， belonging to the high sensitivity. The MIC of the honeysuckle and coptis were 625 mg·mL-1， 3125 mg·mL-1， MBC were 125 mg·mL-1， 625 mg·mL-1. The KirbyBauer method was the best in vitro bacteriostasis test method， the best bacteriostasis effect of 10 kinds of Chinese herbal medicine against avian E.coli were honeysuckle and coptis．

Key words: chinese herbal medicine, avian E. coli, external bacteriostasis experiment, minimum inhibitory concentrations, minimum bactericidal concentrations