Abstract: The effects of adding compound micro-ecological preparation and feed antibiotics on the serum biochemical indices and intestinal enzyme activity of broilers were studied. Five hundred one-day-old female AA broiler chicken were randomly divided into five groups with 4 repetitions in each group and 25 chickens per repetition. The pre-trail period of the experiment was 7 days. The chicken in the control group（groupⅠ）were only fed with the basal diet（no antibiotics）,chicken in groupⅤwas fed with antibiotics and chicken in group Ⅱ,Ⅲ and Ⅳ were fed with feeding the diet with adding 1.0‰,2.0‰ and 4.0‰ micro-ecological preparation. The test period lasted for 35 days. The results showed that the content of serum total protein in group Ⅲ in each test stages was significantly higher than that in control group and antibiotics group（P0.05）, except 42-day-old. Except 14- day-old, the content of serum urea nitrogen in group Ⅲ of broilers was significantly lower than that in control group and antibiotics group （P0.05）. In all test stages, the activity of protease in ileum contents in group Ⅲ was significantly higher than that in control group and antibiotics group （P0.05）. And the activity of protease in jejunum contents in group Ⅲ was significantly higher than that in control group and antibiotics group （P0.05）, except 14-day-old. Except 14-day-old, the activity of amylase in ileum and jejunum contents in group Ⅲ was significantly higher than that in control group and antibiotics group（P0.05）. Therefore, 2.0‰ compound micro-ecological preparation could significantly increase the level of total protein in the serum of broilers, enhance the activities of protease and amylase in ileum and jejunum contents and decrease the content of serum urea nitrogen of broilers to some degree.