Abstract: The micro-ecological preparation peptin was added in the diet of broilers to measure the growth performance,physiology of alimentary tract and intestinal microflora of broilers.And the application effects of peptin in the production of broilers were discussed.The results showed that both aureomycin and peptin could significantly increase the 21-day-old body weight,the average daily gain from the 1st day to the 21st day and the feed-meat ratio of broilers（P〈0.05）.From the view of feed-meat ratio,adding peptin and aureomycin could decrease the feed-meat ratio from the 1st day to the 21st day.The feed-meat ratio in different groups of peptin was lower than that of aureomycin group,without significant difference（P〉0.05）.Peptin could significantly decrease the relative length of duodenum,jejunum and whole small intestine of 21-day-old broilers,significantly increase the relative length of ileum（P〈0.05）.Aureomycin had no significant effect on the length of duodenum,jejunum and whole small intestine（P〉0.05）,but it significantly increased the relative length of ileum（P〈0.05）.On the 42nd day,peptin only significantly increased the relative length of jejunum,but it had no significant effect on other intestinal segments（P〉0.05）.While aureomycin had no significant effect on the length of duodenum,jejunum,ileum and whole small intestine of 42-day-old broilers（P〉0.05）.Aureomycin and peptin had no significant effect on the villus height,recess depth and the ratio of villus height to recess depth in duodenurn,jejunum and ileum of 21-day-old or 42-day-old broilers（P〉0.05）,but there was an increasing tendency.Peptin had the tendency of increasing the lactobacillus number and decreasing the number of Escherichia coli in the contents of cecum in 21-day-old broilers and there was no significant difference in different groups.While aureomycin significantly decreased the number of lactobacillus and Escherichia coli（P〈0.05）.To sum up,peptin could enhance the production performance of broilers,improve the intestinal morphology,increase the number of lactobacilli and decrease the number of Escherichia coli,and the effects in early stage was better than that in late stage.