Abstract: This experiment was conducted to investigate the effects of compound probiotics on henhouse environment， growth performance， nutrient digestibility and serum biochemical indices of broilers. Four hundred one\|day\|old female broiler chickens were randomly divided into 4 groups with 4 replicates in each group and 25 chickens per replicate. The chickens in the control group（groupⅠ） were fed with a basal diet， and group Ⅱ， Ⅲ and Ⅳ were fed with the basal diet supplemented with 01%， 02% and 04% compound probiotics， respectively. The results showed as follows: 1） Compared with the control group， the average daily gain of broilers in group Ⅲ was significantly higher（P<005）， feed/gain （F/G） and death rate were significantly lower（P<005）; 2） The concentrations of NH3 and H2S were significantly reduced in each treatment group（P<005）; 3） Compound probiotics could significantly improve the digestibilities of crude protein， Ca and P in broilers（P<005）， also increase the concentration of total protein and activities of cholinesterase and α\|amylase in broiler serum. In conclusion， the supplementation of 02% compound probiotics can improve the growth performance， significantly increase the serum indices and nutrient digestbilities of broilers （P<005）， also had a better effect on improving the environment of henhouse.

Key words: compound probiotics, broiler, performance, NH3, H2S, nutrient digestibility, serum indices