This experiment was conducted to study the effects of active yeast on intestinal health of yellow-feathered broilers challenged by lipopolysaccharide (LPS). Four hundred and eighty one-day-old male yellow-feathered broilers were randomly allotted to six groups with eight replicates per group and ten broilers per replicate. The broilers in antibiotic group were fed with the basal diet supplemented with 0.025‰ antibiotic, that in antibiotic+LPS group were fed with the basal diet supplemented with 0.025‰ antibiotic and injected with LPS, that in 0.05% active yeast group were fed with the basal diet supplemented with 0.05% active yeast, that in 0.05% active yeast+LPS group were fed with the basal diet supplemented with 0.05% active yeast and injected with LPS, that in 0.50% active yeast group were fed with the basal diet supplemented with 0.50% active yeast, and that in 0.50% active yeast+LPS group were fed with the basal diet supplemented with 0.50% active yeast and injected with LPS. The experiment lasted for 56 d. Broilers aged at 21, 23, 25 and 27 days in antibiotic+LPS group, 0.05% active yeast+LPS group and 0.50% active yeast+LPS group were injected intramuscularly with 2 mL 0.2 mg/mL LPS per broiler, and the others were injected intramuscularly with same volume saline. The rectal temperature of broilers aged at 21 and 27 days were measured at 2, 4, 6, 8, 10, 12 and 24 h after the injection of LPS or saline, and the apoptotic index of intestinal cell of broilers aged at 27 and 56 days, microflora number of intestinal chyme and intestinal morphology of broilers aged at 27, 35 and 56 days were detected. The results showed as follows: 1) compared with saline injection, LPS challenged significantly increased the rectal temperature of yellow-feathered broilers at 2 h after injection aged at 21 days and at 2 h and 4 h after injection aged at 27 days (P<0.05), and significantly decreased the rectal temperature of yellow-feathered broilers at 12 h after injection aged at 21 days and at 8 h after injection aged at 27 days (P<0.05). Dietary active yeast had no significant effect on the rectal temperature of yellow-feathered broilers (P>0.05), and dietary active yeast and intramuscular injection of LPS had no significant interaction on the rectal temperature of yellow-feathered broilers (P>0.05). 2) Compared with saline injection, LPS challenged significantly increased the apoptotic index of duodenum and ileum of yellow-feathered broilers aged at 27 days (P<0.05). Dietary active yeast had no significant effect on the apoptotic index of intestinal cell of yellow-feathered broilers (P>0.05), and dietary active yeast and intramuscular injection of LPS had no significant interaction on the apoptotic index of intestinal cell of yellow-feathered broilers (P>0.05). 3) Compared with antibiotic, dietary 0.05% and 0.50% active yeast significantly increased the Saccharomycetes number of ileal chyme of yellow-feathered broilers aged at 27, 35 and 56 days (P<0.05). Compared with saline injection, LPS challenged had no significant effect on the microflora number of ileal and cecal chyme of yellow-feathered broilers (P>0.05). Dietary active yeast and intramuscular injection of LPS had no significant interaction on the microflora number of intestinal chyme of yellow-feathered broilers (P>0.05). 4) Compared with antibiotic, dietary 0.50% active yeast significantly increased the villus height of jejunum of yellow-feathered broilers aged at 35 days (P<0.05). Compared with saline injection, LPS challenged significantly increased the crypt depth of duodenum of yellow-feathered broilers aged at 56 days (P<0.05). Dietary active yeast and intramuscular injection of LPS had no significant interaction on the intestinal morphology of yellow-feathered broilers (P>0.05). In conclusion, the immune stress of yellow-feathered broilers is successfully induced by LPS, and dietary active yeast can increase the intestinal villus height and Saccharomycetes number of chyme, improve the intestinal mucosa and microflora structure of yellow-feathered broilers, but intramuscular injection of LPS and dietary active yeast have no significant interaction.