This study was conducted to determine the effects of substitution of fermented protein feed for soybean meal on growth performance, nutrient digestibility and intestinal microflora of broiler chickens. Two hundred 6-week-old broilers were randomly divided into 4 groups, and 5 replicates in each group with 10 broilers in each replicate. The control group was fed the basal diet, and group Ⅰ to group Ⅲ were fed the basal diet in which 90%, 60% and 30% soybean meal were replaced with fermented protein feed. The experiment lasted for 2 weeks. The results showed that fermented protein feed replacing 30% soybean meal in basal diet had no significant effects on average daily gain (ADG), ratio of feed to gain (F/G), the digestibilities of crude protein, crude fat, calcium and total phosphorus, and the number of intestinal Lactobacillus (P>0.05). But the diarrhea rate and the number of rectal E. coli in groups Ⅱ and Ⅲ were significantly decreased compared with the control group (P<0.05). In conclusion, fermented protein feed replacing 30% soybean meal in basal diet had no significant effects on growth and nutrient digestibility of broiler chickens on the basis of decreasing feed cost, and decreased significantly the number of E. coli and diarrhea rate of broiler chickens.［Chinese Journal of Animal Nutrition, 2010，22（2）:352-357